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HomeMy WebLinkAbout6 - Landmark Alteration Certificate for installation of an exterior condensing unit for the porpertyMemo to the Landmerks Preservatlon Advisory Board Re: Request for Lendmerk Alieration CeAlflcate for Cotlage 20, Chautauqufl ~~ ~ ~ MEMORANDUM ~ n~~~~~ '"~ ~' I ~~~ ~~ a, ~~ ~ I~' April 2, 2003 '''~~\"""~~ TO: `j~~~~~ Landmarks Preservation Advisory Board ~~~ ~~ FRO~ Ruth McHeyser, Director of I,ong Range Planning Neil Holthouser, Planner SUBJ~CT: Request to grant a Landmark Alteration Certificate for instailation of an exterior ~ ~~1~ condensing unit for the property at 20 Chautauqua Puk, within the Chautauqua `~r;~ ,~~~ ~~ Historic District. ~ ',` ~~1 r• Applicant: Alice Crawford Thomas ~y ~~~~\~ ~ `11~U1~ • ~ ~ N X~~~\ M~` ~ ~~~~U~~,~p \ ~~~,`~ ~~tiN) ~V 1 STATISTICS: ~1. Site: 2. Zoning: 3. Owner: 4. Applicant: BACKGROUND; 20 Chautauqua Park LR-E (I.ow-Density Residentiai, Established) Alice Crawford Thomas Alice Crawford Thomas; Kristin I.ewis, architect ~~1\~ On Mazch 13, 2003, the Planning Department received an application for a Landmazk Alteration '}7~ Certificate to install an exterior condensing unit for the property at 20 Chautauqua Park, located within the Chautauqua Historic District. (See Attachment A: Application and Proposed Plans.) Prior to submitting a formal application, the applicant met with the Landmarks design review committee to discuss conceptual locations for an exterior condensing unit. The committee expressed concerns about the potential visual impacts of exterior condensing units within the district, given the close proximity of residential structures to each other and the open camp-like setting of the district. The committee determined that the proposed exterior condensing unit could have a significant impact on the special character and special historical, architectural, and aesthetic interest and value of the Chautauqua Historic District. The committee therefore refened the request to the full Landmazks Boazd for a public hearing, as required by,the Historic Preservation Code. (See Attachment B: Design Review Committee comments.) In addition to Landmarks review and approval, exterior alterations within the Chautauqua Historic District must also be reviewed by the Chautauqua Association's buildings and grounds committee. The applicant met with the buildings and grounds committee in 7uly 2002 to conceptually discuss plans for an exterior condensing unit. As a result of that meeting, the Chautauqua Association sent a memorandum to the Landmuks design review committee, encouraging the committee to consider the potential impacts of exterior condensing units within the Chautauqua Historic District. (See Attachment C: Memorandum from Chautauqua Association. ) The Chautauqua Association raised the following issuas: Memo to the Landmarks Praservation Advisory Board Re: Request tor Landmark Alteratlon Certificate for Cotlage 20, Chautauqua 1. Approval of an exterior condensing unit will likely lead to additional requests. 2. Noise generated by exterior condensing units could impact the quality of life for Chautauqua res,iclents, given the close proximity of cottages and Chautauqua's emphasis on outdoor recreation and use of porches. 3. The Chautauqua Association received a Landmark Alteration Certificate in July 2000 to install two exterior HVAC condensing units on the west side of the Missions House, within the Chautauqua Historic District. 4. The Chautauqua Association is currently developing a Cultural Landscape Assessment and Master Plan; the potential impacts of exterior condensing units may be considered as part of the Cultural Landscape Assessment. At this time, the Chautauqua Cultural Landscape Assessment has not been completed. The preliminary draft report does not address the issue of exterior condensing units or mechanical systems. REQUEST: The applicant initially submitted plans showing four al[ernative locations for an exterior condensing unit: 1. To the side of the house (north elevation) adjacent to an existing chimney; 2. On the patio at the rear of the cottage, adjacent to an existing bedroom window; 3. On the patio at the reaz of the cottage, adjacent to the breakfast room; 4. In a partially-enclosed utility area at the rear of the cottage. Under alternative #1, the condensing unit would be visible from the street (Kinnikinik) and from the open space and trail system to the west (Bluebell). Under alternatives #2 and 3, the unit would be visible from the open space and trail system to the west. Under alternative #4, the unit would not be visible from public view, since it would be located in a recessed area and screened by an existing stone retaining wall and partially enclosed utility azea. Based on conversations with staff subsequent to formal submittal, the applicant has amended the request to include only alternative #4. The Board should disregard other alternative locations shown on the plans. KEY ISSUES: In considering this request, staff recommends that the Board answer the following key questions: 1. What is the Landmarks Board's purview in this request vis-~-vis the Historic Preservation Code? 2. What do the design guidelines say about exterior condensing units? 3. What elements define the "special character" of the site and the Chautauqua Historic District? 4. How will the proposed exterior condensing unit affect this special character? 2 Memo to ihe Landmarks Preservatlon Advisory Board Re: Raquest for Lendmark Afleretlon Certificate for Cotlage 20, Chautauqua If the Boazd finds that the proposed exterior condensing unit would have an adverse impact on the site or historic district, then it should deny the request. If the Board finds that the request would not have an adverse impact on the site or historic district, staff recommends that the Boazd conditionally approve the request and refer the application to the Landmazks design review committee for review and approval of final placement and details. ANALYSIS: The Historic Preservation Code sets forth the standards the Landmarks Board must apply when considering a request for a Landmark Alteration Certificate. In addition, the Board has adopted the Chautauqua Design Guidelines to help interpret the Historic Preservation Code. Though not formally adopted, the Board may also consult the draft General Design Guidelines for residential districts and individual landmarks. The Historic Preservation Code requires Landmarks approval for any exterior alteration within a designated historic district. The code sets forth the following standards for issuance of a Landmazk Alteration Certificate: (a)VThe landmarks board and the city council shall not approve an application for a landmark alteration certificate unless each such agency linds that the proposed work is consistent with ihe purposes of this chapter. (b) Neither the landmarks board nor the city council shall approve a landmark alteration certificate unless it meets the following conditions: (1)The proposed work preserves, enhances, or restores and does not damage or destroy the exterior architectural /eatures of the landmark or fhe subject property within an historic district; (2)The proposed work does not adversely aHect the special character or special hisforical, architectural, or aesthetic interest or value of the landmark and its site or the district; (3)The architectural sryle, arrangement, texture, color, arrangement of color, and materials used on existing and proposed structures are compatible with the characte~ of fhe existing landmark and its site or the historic districh and (4)With respect to a proposal to demolish a building in an historic district, the proposed new consfrucfion fo replace the building meets the requirements of paragraphs (b)(2) and (3) of this sec~ion. (c) In determining whether to approve a landmark alteration certilicate, the landmarks board shall consider the economic /easibility of alternatives, incorporation of energy-efficient design, and enhanced access for fhe disabled. The Historic Preservation Code refers primazily to the visual, architectural, and aesthetic impacts of the Landmark Alteration Certificate application. The code also refers to the "special character" of the district, which includas non-architectural features such as the quality of open space and the relationship of buildings to each other and to their natural environment. Staff believes that the code does not permit the Board to consider impacts related to noise or the intended use of the property. According to the Chautauqua Design Guidelines, the historic district is characterized by simple cottage architecture in a park setting, creating a"unique rural enclave on the edge of a dense urban grid." The cottages are located on small lots averaging approximately 3,500 square feet; buildings are set close to the street with minimal side yard setbacks. The residential structures all face the interior of the site. However, the distinction between the "front" and "back" of each individual structure is blurred by open camp-like setting, the close proximity of buildings to each other, and the 3 3 Memo to the Landmarks Preservation Advisory Board Re: Request tor Lantlmark Alteration Certificate for Cottage 20, Chautauqua lack of fences, hedges, or other means of sepazating and delineating properties. Structures in the interior of the district (i.e. those located along cross streets and alleys) are visible from all sides. Structures located on the periphery of the district (i.e. those along the west side of Kinnikinik and the east side of Goldenrod) are visible not only from the street, but also from the public open space and trail system surrounding the district. Staff believes that this quality of openness and visual accessibility is a defining characteristic ofthe district. The Chau[auqua Design Guidelines recognize that the district is comprised of a vaziety of building sizes and styles, and that not al] of the guidelines will apply to all projects. The guidelines do not specifically address the issue of exterior HVAC systems or condensing units. However, in addressing issues related to energy conservation, the guidelines state: "The preservation of the natural ventilation of cottages is encouraged." Staff does not believe that the guidelines intend to prohibit air conditioning or climate control systems, but rather to preserve the openness of porches and the operability of historic windows. Staff notes that many cottages and buildings in Chautauqua cunently make use of portable window air conditioning units. These units are temporary and not permanently affixed to the structure, and are not subject to Landmarks review and approval. The guidelines go on to address the appropriateness of additions and the relationships of buildings to each other and the natural environment: "Maintain the same spacing between buildings. Additions fo many cottages will be dilficult to achieve, but should be confined to the rear of the building. Where there is more open space surrounding larger6uildings, this space should be carefully preserved. ... The lack of disfinction between properties should be preserved. Property lines should not be defined by fences or landscape material so that the camp character of the park will be preserved." Staff believes that the guidelines intend to preserve the qualities of openness, un-delineated space, and visual accessibility within the district. The guidelines acknowledge that new additions to existing structures may not always be possible, based on the degree of visibility and the relationship of the building to other buildings and the natural environment. If an addition is to be considered, the guidelines recommend that the new addition be located to the rear, where it would have the least visual impact. Staff believes that this rationale extends to the introduction of exterior mechanical systems and condensing units. If such units are to be considered, staff believes they should be located in such a manner that is not visible from public view - including streets, alleys, public open space and public trails - and would not disrupt the qualities of openness, un-delineated space and visual accessibility. ~ Though not formally adopted by the Board, the General Design Guidelines recommend that new mechanical systems, including condensing units, should be located in an inconspicuous location and should be screened from view. The General Design Guidelines state: 'lf a new mechanical system is needed, install it so that it causes the least amount of alteration to the building's exterior facades, materials, and site features. ... Locate new mechanical equipment and utilities, including heating and air conditioning units, in the most inconspicuous area, usually along a building's rear /agade. Screen them from view." 4 4 Memo to the Landmarks Preservation Advisory Board Re: Request for Landmark Alteration Certificate for Cottage 20, Chaufauqua Staff believes that, given its unique camp-like setting, there are few locations in the Chautauqua Historic District that are truly "inconspicuous" and not visible from public view, It may not always be possible to locate an exterior mechanical unit in a manner that is not publicly visible, even along a building's rear fa~ade. Although the General Design Guidelines recommend screening of mechanical units, staff believes such screening may not be appropriate in the Chautauqua Historic District, given the lack of fences and formal landscaping. Staff believes that screening should not be allowed to interrupt the qualities of openness and un-delineated space within the district. With respect to the subject request for an exterior condensing unit at Cottage #2Q staff believes that the proposed work meets the standards set forth in the Historic Preservation Code, the Chautaucjua Design Guidelines, and the General Design Guidelines. The proposed location would not be visible from public vantage points, including the street and public open space and trails located to the west of the subject property. The unit would be recessed in a partially enclosed utility area along the rear fapade, immediately adjacent to a 4' high stone retaining wall. The unit would not require additional screening, and would not disrupt the open and un-delineated space between cottages. NEIGHBORHOOD COMM~NT: Staff has received a memorandum from the Colorado Chautauqua Association, included as Attachment C. In addition, staff has received comments from three neighboring cottage owners in favor of the request, included as Attachment D. FINDINGS: Staff recommends that the Board adopt the following findings: 1. The request for a Landmark Alteration Certificate for installation of an exterior condensing unit for the property at 20 Chautauqua Pazk is consistent with the Historic Preservation Code, in that the proposed work would not have an adverse impact on the special character or special historical, architectural, or aesthetic interest or value of the site or historic district. 2. The request is compatible with the Historic Preservation Code and the Chautauqua Design Guidelines, in that the proposed exterior condensing unit would not be visible from public view and would not,disrupt the qualities of openness, un-delineated space, and visual accessibility that define the character of the site and historic district. PLANNING DEPARTMENT RECOMMENDATION: The Planning Department recommends that the Landmarks Board conditionally approve the request for installation of an exterior condensing unit for the property at 20 Chautauqua Park, as shown on the submitted plans as alternative #4, adopting the staff inemorandum as 5ndings of the Board, and referring the request to the Landmarks design review committee for review and approval of final placement and details. . 5 5 Memo to ihe Landmarks Preservation Advisory Board Re: Request for Landmark Alteration Certificate for Cottage 20, Chautauqua ATTACHMENTS: Attachment A: Application and Proposed Plans Attachment B: Design Review Committee comments Attachment C: Memorandum from Chautauqua Association Attachment D: Neighborhood Comment Attachment E: Preservation Brief #24 FROM : CHAUTRU~UR ASSOC . Ne Date of inltial Property addr Owne~ (if not the Mailing address. Owner's represen ATTACHMENT A aH~., ~~2~00 Mar. 25 2963 09:37RM P1 __ IFICA7E APPLICATION ~. Relationship to project (e.g., archicect, contractor) The Design Review Committee of the Landmark Preservation Advisory Board must review proposed alterations to landmark properties or properties within designated historic districts. 7he committee is composed of two members of the Landmark Preservatfon Advisory Board and one Pianning Department staff member: The committee meets every Wednesday beginning at 8:30 PM. To assist us in reviewing your project, please provide a project description in the spate provided below. Include al! of the exterior alterations proposed for the property. Feel free to use the reverse side for additonal comments. Please bring the completed app{ication with you to your first design review meeting. If you have questions, or to schedule an appointment for review, please contatt Judith Sanders at (303) 441-4293. Welook forward to working wi#h yau on your proposal! PROIECTDESCRIP7~Otv [Pleaselistaliexterioralteradorisproposedfortheproperty.J '~~a,.e ~ullc~l~ '~a Q~-' l~~'S c.o~~or~ - r~wc,~ue aw~~.~ lo~.~kvw~ a.elda.EN,vy i'Sor~,¢ fe~w w~Kda.us ~ sµ~p ~ wu~-rlt a'I~t, SttA~a I~dr~o~ . - ~de~.~ ~ ~ ~ ~ u~t- ~- °-1°P~x ~ •.1 ~~,rc~4¢ tna,w a.e.ca.o ~ b -~a.u9 b~'~'^~ " e u' ~~'' ~ o W ~ w r~. w r- ~#' ~{°~e Lot size (in square feet) Total e~usting square feet~a953 Existing height TYP.~. S~F AI TERATION [Please check all that apply.] ~ New construdion/AddRio~ ~,Rear ~.Side _FroM ~P,dditional Story Ncw Garage (requi~s publrc heann~ ~Demoiition (r~quirrspublicheann~J ~,Dormer(s) Proposed addidonal sq. ft. ~$ ~'f ~ ~~g ~ Proposed hcight j.l A _ ~Porch _Deck ^Skylight(s) ~Window(s) ,~_Door _~Paint ____Fence front yard ____side yard ~rear yard ` -~ New roof _~Repair _Other (please speci/y) ATTACHMENT B Date: ~ . 2~ , 2002 Landmark Alteration Certifcate `~ or Demolition / Moving Address of Property: ~-~~ ~,~ '* ~ t~ttriVTNJQJ/c Owner'sName: lc~.~S.~c~l ~~-w~~ +tt~c~rt~~ DRCMembers: l.1Sn E~c r~- LEt,ATIp 2uW-~rt. NE~L t~~-rtrr,u~~Ji Remarks: - ~~g~-qv.-/~liorL ~ rK'~~~tKOR- ~r3cc-~ Lorl~E.~l.S131Z-- VK~r ~*~. MA`~C ttT'JE- ~t- 5~~+<<Plu~r tt~.Phcx- o~ StTE p~Stauu- T~CB-~- V`[oJI.A~ R~.f-EJL 1NayJE.ST '~`o F-UIJ~- LA1~~DMA~-K~S $o~.~ ~yz p~P,,,uc.. ~-Aruniq ~ _ ~uW-,-iac~ -i~~s ~k.. ~-~'"- v~r/ c.y{.~'~cx"h rtssoun3+an) ~.~~. 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Public hearing: Y N S:~PLAN\data\Co mdev\Hf S"I~GEN\ALTCERTS\LAC-app,etc\CommenlsPage2. doc 8 Date: ~ ~ • ~ ~P , 2002 Landmark Alteration Certit"icate // or Demolition / Moving Address of Property:, ~~ ~ ~ ~ ~ ~"^~~"^~ ° "R Owner's Name• ~u.~.s~latr~ L Y-r`r~`Ti*~ «°`*~ `S DRC Members: ~•~.~P• ~,,ct~ t.e.~*'1° ~`°c.'~'L µs~~ t'+°`at+°°sr~ Remarks: - c,~.~su~t' ..v ~ ~w+v.~~Y~`~vPt- ~~4. °, ~,1zovApS c.~N~.~'l~_ - {~htCL~ 1~~~~-' \`~~ ~1 V<.ooA wL ~t~1D'0"1S ati1 ~(.(,~.ST ~C,'~-~hhG~ 01~- ~ ..~~~ ~NarJc.- ~t,AR~Lfc.O END, Pg.~r~_D~~ ~,~.~s-cs ~ t~~~- F*~rc. sr,N~uklz, ~~ru./~ PvJBVC-rw~5 ~Nln~DOV~LS . ~ t NAe.,.X.., ~ ot3TC-' oJEfL - ~1~C. .--~r~~ ~ o~F- `~o (2tT~.r'n~cL'- aooR. ~0 24~3t- pM,"7~l 11~1Lti~0~~c~ 51P~C. 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Public hearing: Y ~ N • ~ ~_ _ S:~PLAN~data\Comdev~EilS'I~GEN4ILTCERTS~C.AC-app,etc\CommentsPage2.doc 10 Memorandum TO: Landmarks Preservation Advisory Board From: Bob D'Alessandro RE; Central Air Conditioning far Chautauqua Cottages Date: July 10, 2002 The issue of centralized air conditioning of a Chautauqua cottage has recently come to my attention. I appreciate the willingness of the Landmarks Preservation Advisory Board to review Ilus application on short notice, especially as ihis is an imporlant decision. In your review, I ask Iha[ you wnsider the following: 1.This is potentially a precedent setting and character re-defining decision. If you clioose to gran[ a permit, it is very likely lhat o[her cottages will even[ually follow sui[. One can imagine a future Chauiauqua in wluch summer residents cloister themselves in air conditioned wttages rather than engage in the sociai, cultural and leaming opportunities that have characterized Chautauqua since 1898. 2. The noise impact created by external air condiuoning units should be carefully evaluated Chautauqua cottages are on non-conforming lots widi minimal setbacks. Whi1e cottages have been insulated in recent years, the noisc insula[ion quality of such insulation is mu~imal. An additional consideration is Aie noise impact on Chautauqua "porch life". As noted in the Design Guidelines, "porches are a one of the most distinctive elements of Chautauqua' . Summer guests and residents have a long tradition of porch sitting especially as U~e cottages are so small and afford no room for socializing. 3. The Colorado Chautauqua Association installed [wo ex[ernal HVAC units on the west side of the Missions House in 2001. In doing sq an important consideration was the fact that the cotlage immediately adjacen[ is the Chautauqua facilitias building and laundry room and not a neighboring wttage. Had this not been the case, an alternalive placement would be have been ident~ed. 4. CCA is currenUy undertaking an extensive cultwal landscape assessment with a Sta[e Historic Fund grant. Perhaps an assessment of the impact of such air conditioning wiits on the character of Chautauqua can be included in the scope of this study, one purpose of which is to avoid unintentional impacts on thc character defining aspects of Chautauqua as we maka changes to its buildings and gounds. T1ie LPAB may want to defer action on the requested pemut until this issue can be better evaluated CHAUIGUQUG PARK 9OO BGSELINE ROGU ` BOUIDER, ~~ •80302 PNONE: 303 442-3282 E-MGIk INFO~(NAUI~UQUG.[OM ~ ~NifflNEC WWW.fHGUTAUQI1A.fOM Fnx: 303 449-0790 11 ATTACHMENT C Attachment D Alice Crawford Thomas 3102 Reba Drive Houston, Texas 77019 March 28, 2003 Dear Grounds Committee: I am the owner of Cottage #20 which was built in the early 1940s by my great grandmother. I am a fourth generation Chautauquan and my children and grandchildren are summer visitors to the cottage. This winter, we began interior renovations to update the wiring, structure, and piping to meet present day code. All of the changes have been approved by I.andmarks and/or have been discussed with Steve Watkins. As part of this project, we would like to remove the six window air conditioning units and replace them with a small, low decibel condenser for a cenVal air and heating system. The condenser would be placed in an approved location. The six window units were added some 10 to 15 yeus ago to mitigate the discomfort resulting from Boulder's increasingly warm summers and the western exposure of our cottage. Importantly, the use of the screened porch on the east side has not been affected by the window units, nor would it be affected by the addition of a central air system. While considering the concept of air conditioning condensers on the Chautauqua grounds, please recall that Chautauqua's own Missions House has two outside condensers. Please also consider the fact that our single condenser would be considerably less obtrusive and make less noise than the existing window units. For generations, we have been leaving Texas each summer to enjoy Coloradds mountains and our Chautauqua friends. We want to encourage the next generation of our family to continue this tradition in pleasant and comfortable conditions. Thank you for your time and consideration. Please call me at 713 524-2744 or email me at ACT524@aol.com iFI can answer any specific questions regazding our current work on Cottage #20. Sincerely, Alice Crawford Thomas ~ I WHOLEHEARTEDLY ENDORSE THIS LETTER AND ITS CONTENTS. THANK YOU-DOSSEI"T MCCULLOUGH, OWNER OF COTTAGE #700 MARCH 26,2003 12 From: <GarPropC~aol.com> To: <Holthousern@ci.boulder.co.us> Date: 3/26/03 8:35PM Subject: Air Conditioner for Cottage 20 Chautauqua Dear Mr Holthouser, I am the current president of Chautauqua Cottagers. I have informed our memtiereship of the proposed plan to replace some six window units with a central unit which would have the compresser and condenser outside. I have received repiies from a number of inembers and none had any objection to this. I favor granting approval to do this. Very truly yours, Neel Garland CC: <ACT524~aol.com> 13 Mar-26-03 12:45P Architects ~, 303 447 2843 P_O~ Bacrbara Sublett Guthery 405 Graciosa Cove, Austin, Texas 75746-6442 Telephone: 512._128.9047, Fax: S 12.328.9082, Cell: 5] 2.426.5 l 15 Email: bsera`hvdroprocessing.com March 8, 2003 Mr. Bob D'Alessandr~~ Executive Director Colorado Chautauqua Association Chautauqua Park 900 Baseline Road Boulder, CO 80302 V[A FACSIMILE: 3U3.449.0790 Dear Bob: It was ~oocl to be bac:k at Chautauqua this week. I hopc wc continuc to get more snow to feed our gounds for next summer. As you ma,y remember, last summer while doing some work on our cottage, the "swamp cooler" which had been in #7 since the 70's N~.~s removed without my permissi~~n or knowledge. When we tried to put it back, I was told that it could not be replaced since the code had changed and wz had lost our grandfather exemption when it was removed. ~Vhen wc then wanted to put an air conditioner under the rear deck, 1 ~vas told that the policy about central air was under review~. However, I was told that I cotild put several window units in the cottage. ns you are now reviewing the policy, I request that you consider allowing central air. [n my particular case, 1 da not perspire as most people do and do not do well when it gets too hot. 1 was not able to stay in my cottage last summer afier the "swamp cooler" was removed. I understand your concern about the noise, however there are now low decibel Icvel air conditioners. ln our cottage, we should be able to put it under the rear deck. I do not believe that the noise would be a problem for 14 Mar-26-03 12:45P Architects 303 447 2843 p p3 my neighbors nor woixld it be as visually obtrusive or as potentially noisy as window units. My great-grandmoth~:r bought Cottage #7 in 1919. We have had five generations at the cottage. My first memories of the cottage are the two summers that my father was overseas during WW1I. Tn 1944 arid 1945, my great-grandmother "PQano" as in "Nano's Nook", my mother, rny aunt and my two cousins and I lived in the cottage both summers. I played tennis across the street for the first time in 1944 at the age of four. We played games with the signs left for the 'iceman so that when folks came back from the mountains, they had 100 pounds of ice instead of 25. We played the pump organ under 1:he Community House; we did crafts; we played on playground equipment that would not be allowed today; and we picnickad when we climbed to the Reservoir or up Flagstaff. And we celebrated VJ Day, remembering that several of our friends had already lost th~~ir fathers. I add these memories so that you understand the depth of my love for Chautauqua. i care about the same things that you do, but [ believe. that air conditioners c<~refully selected and placed can enhance Chautauqua. We are all adjusting to the ~~hanges in our climate, and 1 have had to .+djust to thc problems that overh~;ating cause me. Thank you for your consideration. Sincercly, /d 1 ,l /y 1'.i ~~tl/E_~ % Barbara Sublett Gulhery Cc: ICristin Lewis Larrv Parrish 15 Preservation Bnef 24: Heating, Venrilating, and Cooling Histonc Build~nes: Yrobtems an... Yage 1 of 16 Attachment E 24 Preservafion Briefs . ~-~~ k ~~~~, 7eehnical Prescrvatian Scn•ic.:s ~ National Park Service Heating, Ventilating, and Cooling Historic Buildings Problems and Recommended Approaches Sharon C. Park, AIA »Hist_o_rLf_Mechanical Systems »Climate Control and Preservation »Planniny the_New _S_~stem ~ »Overyiew of_HVAC S~ste_ms » _ Designing the_ new_system »Systems_Performance and Maintenance »HVAC Do's and Don'ts »Conclusion »Bibliography The need for modern mechanical systems is one of the most common reasons to undertake work on historic buildings. Such work includes upgrading older mechanical systems, improving the energy efficiency of existing buildings, installing new heating, ventilation or air conditioning (HVAC) systems, or--particularly for museums-- installing a climate control system with humidification and dehumidification capabilities. Decisions to install new HVAC or climate control systems often result from concern for occupant health and comfort, the desire to make older buildings marketable, or the need to provide specialized environments for operating computers, storing artifacts, or displaying museum collections. Unfortunately, occupant comfort and concerns for the objects within the building are sometimes given greater consideration than the building itself. In too many cases, applying modern standards of interior climate comfort to historic buildings has proven detrimental to historic materials and decorative flnishes. This Preservation Brief underscores the importance Qf careful planning in order to balance the preservation objectives with interior climate needs of the building. It is not intended as a technical guide to calculate tonnage or to size piping or ductwork. Rather, this Brief identiFies some of the problems associated with installing mechanical systems in historic buitdings and recommends approaches to minimizing the physical and visual damage associated with installing and maintaining these new or upgraded systems. Historic buildings are not easily adapted to house modern precision mechanical systems. Careful planning must be provided early on to ensure that decisions made during the design and installation phases of a new system are appropriate. Since new mechanical and other related systems, such as electrical and fire suppression, can use up to 10% of a building's square footage and 30%-40~h of an overall rehabilitation budget, decisions http://www. cr.nps.gov/hps/tps/briefs/brief24.htm 3/24/2003 16 YreservaUon Bnet 24: Heanng, Venhlaung, Aild I~OOl1Dg ti1STO17C tSUll(11Rg5: r[uutcu~~ nu.., ragc ~ ~i w must be made in a systematic and coordinated manner. The installation of inappropriate mechanical systems may resuit in any or all of the foilowing: . large sections of historic materials are removed to install or house new systems. • historic structural systems are weakened by carrying the weight of, and sustaining vibrations from, large equipment. . moisture introduced into the building as part of a new system migrates into historic materials and causes damage, including biodegredation, freeze/thaw adion, and surface staining. • exterior cladding or interior finishes are stripped to install ~ew vapor barriers and insulation. . historic finishes, features, and spaces are altered by dropped ceilings and boxed chases or by poorly located grilles, registers, and equipment. . systems that are too large or too small are installed before there is a clearly planned use or a new tenant. For historic properties it is critical to understand what spaces, features, and finishes are historic in the building, what should be retained, and what the realistic heating, ventilating, and cooling needs are for the building, its occupants, and its contents. A systematic approach,involving preservation planning, preservation design, and a follow-up program of monitoring and maintenance, can ensure that new systems are successfuily added--or existing systems are suitably upgraded--while preserving the historic integrity of the building. The dropped ceilings covering an air conditioning system alsa coverihe historic windows, al[ering their No set formula exists For determining what type proportion and resulting in loss of the historic of inechanical system is best for a specific character. Photo: NPS files. building. Each building and its needs must be evaluated separately. Some buildings will be so significanC that every effort must be made to protect the historic materials and systems in place with minimal intrusion from new systems. Some buildings will have museum collections that need speciai climate control. In such cases, curatorial needs must be considered--but not to the ultimate detriment of the historic building resource. Other buildings will be rehabilitated for commerciat use. For them, a variety of systems might be acceptable, as long as significant spaces, features, and finishes are retained. Most mechanical systems require upgrddin9 or rep-acement within 15-30 years due to wear and tear or the availability of improved technology. Therefore, historic buildings should not be greatly altered or otherwise sacrificed in an effort to meet short-term systems objectives. History of Mechanical Systems The history of inechanical systems in buildings involves a study of inventions and ingenuity as building owners, architects, and engineers devised ways to improve the interior climate of their buildings. Following are highiights in the evolution of heating, ventilating, and cooling systems in historic buildings. http://www. cr.nps.gov/hps/tps/briefs/brief24.htm 3/24/2003 17 Yreservahon tsnet 2a: tiearing, venuianng, ann l;ootmg tnstonc tsuuamgs: rroo~ems aa.. rage s oi io Eighteenth Century. Early heating and ventilation in America relied upon common sense methods of managing the environment. Builders purposely sited houses to capture winter sun and prevaiiing summer cross breezes; they chose materials that could help protect the inhabitants from the elements, and took precautions against precipitation and damaging drainage patterns. The location and sizes of windows, doors, porches, and the floor plan itself often evolved to maximize ventilation. Heating was primarily from fireplaces or stoves and, therefore, was at the source of delivery. In 1744, Benjamin Franklin designed his "Pennsylvania stove" with a fresh air intake in order to maximize the heat radiated into the room and to minimize annoying smoke. Thermal insulation was rudimentary--often wattle and daub, brick and wood nogging. The comfort level for occupants was low, but the relatively small difference between internal and external temperatures and relative humidity allowed buflding materials to expand and contract with the seasons. Regional styles and architectural features reflected regional climates. In warm, dry and sunny climates, thick adobe walls offered sheiter from the sun and kept the inside temperatures cool. Verandas, courtyards, porches, and high ceilings also reduced the impact of the sun. Hot and humid climates called for elevated living floors, louvered grilles and shutters, balconies, and interior courtyards to help circulate air. Nineteenth Century. The industrial revolution ~. ~',~ I' i provided the technological means for controlling the ~I~~' ~ environment for the first time. The dual developments 3~- ~ of steam energy from coal and industrial mass -~~ production made possible early central heating systems 19thcenturybuildingsusedporches, with distribution of heated air or steam using metal comiortable in 1ne ummeraPhoto: NPSre ducts or pipes. Improvements were made to early nies. wrought iron boilers and by late century, steam and low pressure hot water radiator systems were in common use, both in offices and residences. Some large institutionai buildings heated air in furnaces and distributed it throughout the building in brick flues with a network of inetal pipes delivering heated air to individual rooms. Residential designs of the period often used gravity hot air systems utilizing decorative floor and ceiling grilles. Ventilation became more scientific and the introduction of fresh air into buildings became an important component of heating and cooiing. Improved forced air ventilation became possible in mid-century with the introduction of power-driven fans. Architectural features such as porches; awnings, window and door transoms, large openwork iron roof trusses, roof monitors, cupolas, skylights and clerestory windows helped to dissipate heat and provide heaithy ventilation. Cavity wali construction, popular in masonry st~uctures, improved the insulating qualities of a building and also provided a natural cavity for the dissipation of moisture produced on the interior of the buiiding. In some buildings, cinder chips and broken masonry filler between structural iron beams and jack arch floor vaults provided thermai insulation as well as fireproofing. Mineral wooi and cork were new sources of lightweight insulation and were forerunners of contemporary batt and blanket insuiation. The technotogy of the age, however, was not sufficient to produce "tight" buildings. http://www.cr.nps.gov/hps/tps/briefsPorief24. htm 3/24/2003 18 There was still only a moderate difference between internal and external temperatures. This was due, in part, to the limitations of early insu~ation, the almost exclusive use of single glazed windows, and the absence of airtight construction. The presence of ventilating fans and the reliance on architecturaf features, such as operable windows, cupolas and transoms, allowed su~cient air movement to keep buildings well ventilated. Building materials could behave in a fairly traditional way, expanding and contracting with the seasons. Twentieth Century. The twentieth century saw intensive development of new technologies and the notion of fully integrating mechanical systems. Oil and gas furnaces developed in the nineteenth century were improved and made more efficient, with electricity becoming the criticai source of power for buiiding systems in the latter half of the century. Forced air heating systems with ducks and registers became popular for all types of buiidings and aliowed architects to experiment with architectural forms free from mechanical encumbrances. In the 1920s large-scale theaters and auditoriums introduced central air conditioning, and by mid-century forced air systems which combined heating and air conditioning in the same ductwork set a new standard for comfort and convenience. The combination and coordination of a variety of systems came together in the post-World War II high-rise buildings; complex heating and air conditioning plants, electric elevators, mechanical towers, ventilation fans, and full service electric fighting were integrated into the building's design. A return air grille is successfully screened behind the arch. Photo: NPS files. construction detail. The insulating qualities of building materials improved. Synthetic materials, such as spun fiberglass batt insulation, were fully developed by mid-century. Prototypes of insulated thermal giazing and integral storm window systems were promoted in construction journals. Caulking to seal out perimeter air around window and door openings became a standard The last quarter of the twentieth century has seen making HVAC systems more energy efficient and better integrated. The use of vapor barriers to control moisture migration, thermally efficient windows, caulking and gaskets, compressed thin wall insulation, has become standard practice. New integrated systems now combine interior climate control with fire suppression, lighting, air filtration, temperature and humidity control, and security detection. Computers regulate the performance of these integrated systems based on the time of day, day of the week, occupanFy, and outside ambient temperature. Climate Control and Preservation Although twentieth century mechanical systems technology has had a tremendous impact on making historic buildings comfortable, the introduction of these new systems in oider buildings is not without problems. The attempt to meet and maintain modern climate control standards may in fact be damaging to historic resources. Modern systems are often over-designed to compensate for inherent inefficiencies of some http://www. cr.nps.gov/hps/tps/briefs/brief24.htm 3/24/2003 19 ~Y~~ ~5 ~ ~ 4 _ ~l f ~ - ~ j ,~~A.a « .. _i., ,. . .. . .,,?:,7.__yc;t~ .,~~ historic buiidings materiais and plan layouts. Energy retrofit measures, such as installing exterior wali insulation and vapor barriers or the sealing of operable window and vents, ultlmately affect the performance and can reduce the life of aging historic materials. In general, the greater the differential between the interior and exterior temperature and humidity levels, the greater the potential for damage. As natural vapor pressure moves moisture from a warm area to a colder, dryer area, condensation will occur on or in building materials in the colder area. Too little humidity in winter, for example, can dry and crack historic wooden or painted surfaces. Too much humidity in winter causes moisture to collect on cold surtaces, such as windows, or to migrate into walis. As a result, this condensation deteriorates wooden or metal windows and causes rotting of ~'~-~°_"' """~~°°°~^ Complez mechanical systems ~for instilutional walis and wooden structural elements, 6uildings may require a central control room. dampening insulation and holding moisture Photo:NPSfiles. against exterior surfaces. Moisture migration through walls can cause the corrosion of inetal anchors, angles, nails or wire lath, can blister and peel exterior paint, or can leave efflorescence and salt deposits on exterior masonry. In cold climates, freeze-thaw damage can result from excessive moisture in external walls. To avoid these types of damage to a historic building, is important to understand how building components work together as a system. Methods for controlling interior temperature and humidity and improving venation must be considered in any new or upgraded HVAC or climate control system. Whiie certain energy retrofit measures will have a positive effect on the overall buiiding, installing effedive vapor barriers in historic walls is difficult and often results in destruction of significant historic materiais. Planning the New Syst~m Climate control systems are generally ciassified according to the medium used to condition the temperature: air, water, or a combination of both. The complexity of choices facing a buiiding owner or manager means that a systematic approach is critical in determining the most suitable system for a building, its contents, and its occupants. No matter which system is installed, a change in the interior climate will result. This physical change will in turn affect how'the building materials perForm. New registers, grilles, cabinets, or other accessories associated witli the new mechanical system will also visually change the interior (and sometimes the exterior) appearance of the building. Regardless of the type or extent of a mechanical system, the owner of a historic building should know before a system is instailed what it will look like and whaC problems can be anticipated during the life of that system. The potential harm to a building and costs to an owner of selecting the wrong mechanical system are very great. The use of a building and its contents will largely determine the best type of inechanical system. The historic building materials and construction technology as well as the size and availability of secondary spaces within the historic structure wili affect the choice of a system. It may be necessary to investigate a combination of systems. In each case, the needs of tiie user, the needs of the building, and the needs of a coliection or http://www. cr.nps.gov/hps/tps/briefs/briefl4.htm 3/24/2003 20 equipment must be considered. It may not be necessary to have a comprehensive climate control system if climate-sensitive objects can be accommodated in special areas or climate-controlled display cases. It may not be necessary to have central air conditioning in a mild climate if natural ventilation systems can be improved through the use of operable windows, awnings, exhaust fans, and other "lowtech" means. Modem standards for climate control developed for new construction may not be achievab~e or desirable fnr historic buildings. In each case, the lowest level of intervention needed to successfully accomplish the job should be selected. Before a system is chosen, the following planning steps are recommended: 1. Determine the use of the building. The proposed use of the building (museum, commercial, residential, retaii) will influence the type of system that should be installed. The number of people and functions to be housed fn a buiiding will establish the level of comfort and service that must be provided. Avoid uses that require major modifications to signiflcant architectural spaces. What is the intensity ot use of the building: intermittent or constant use, special events or seasonal events? Will the use of the buiiding require major new services such as restaurants, laundries, kitchens, locker rooms, or other areas that generate moisture that may exacerbate climate control within the historic space? In the context of historic preservation, uses that require radical reconfigurations of historic spaces are inappropriate for the building. 2. Assemble a qualified team. This team ideally should consist of a preservation architect, mechanical engineer, electrical engineer, structural engineer, and preservation consultants, each knowledgeable in codes and local requirements. If a special use (church, museum, art studio) or a coliection is involved, a specialist familiar with the mechanical requirements of that building type or colfection should also be hired. Team members should be familiar with the needs of historic buildings and be able to balance compfex factors: the preservatioo of the historic architecture (aesthetics and conservation), requirements imposed by mechanical systems (quantified heating and cooling loads), building codes (health and safety), tenant requireme~ts (quaiity of comfort, ease of operation), access (maintenance and future replacement), and the overall cost to the owner. 3. Undertake a condition assessment of the existing building and its systems. What are the existing construction materials and mechanical systems7 What condition are they in and are they reusabte? Where are existing chiilers, boilers, air handlers, or cooling towers located? Look at the condition of all other services that may'benefit from being integrated into a new system, such as electrical and fire suppression systems. Where can ener9y efficie~cy be improved to help downsize any new equipment added, and which of the historic features, e.g. shutters, awnings, skylights, can be reused? Evaluate air infiltration through the exterior envelope; monitor the interior for temperature and humidity levels with hygrothermographs for at least a year. Identify building, site, or equipment deficiencies or the presence of asbestos that must be corrected prior to the installation or upgrading of inechanical systems. 4. Prioritize architecturally significant spaces, finishes, and features to be preserved. Significant architectural spaces, finishes and features should be identified and evaluated at the outset to ensure their preservation. This includes significant existing mechanical systems or elements such as hot water radiators decorative grilles, elaborate switch-plates, and nonmechanical architecturai features such as cupolas, transoms, or porches. Identify nonsignificant spaces where mechanical equipment can http:!/www. cr.nps.gov/hps/tps/briefs/briefl4.htm 3/24/2003 21 Yreservanon tsnet z4: tieanng, vennianng, ana ~ooimg rusLOnc nw~wi~gs: r,ou~ciiw xn... ragc ~ ~. ~., be placed and secondary spaces where equipment and distribution runs on both a horizontal and vertical basis can be located. Appropriate secondary spaces for housing equipment might include attics, basements, penthouses, rrtezzanines, false ceiling or Floor cavities, vertical chases, stair towers, closets, or exterior below-grade vaults. ~ 5. Become famlliar with local building ~~"~~ ~ and fire codes. Owners or their ~:. representatives should meet early and often `~, '` ` ..,- with local o~cials. Legal requirements should Cy be checked; for example, can existing ~~z ductwork be reused or modified with ' dampers? Is asbestos abatement required? What are the energy, fire, and safety codes ~ ~ ! and standards in ptace, and how can they be ~~~ j,; met while maintaining the historic character , of the building? How are fire separation walis -~ ~ and rated mechanical systems to be handled The flexible duct work, seen here, can be used to between multiple tenants? Is there a advantage in tight attic spaces. Photo: NPS files. requirement for fresh air intake for stair towers that will affect the exterior appearance of the building? Many of the health, energy, and safety code requirements wili inFluence decisions made for mechanical equipment for ciimate controi. It is importance to know what they are before the design phase begins. 6. Evaluate options for the type and size of systems. A matrix or feasibility studies shouid be developed to balance the be~efits and drawbacks of various systems. Factors to consider include heating and/or cooling, fuel type, distribution system, control devices, generating equipment and accessories such as filtration, and humldification. What are the initial i~stallation costs, projected fuel costs, long-term maintenance, and life-cycle costs of these components and systems? Are parts of an existing system being reused and upgraded? The benefits of added ventilation should not be overlooked. What are the tradeoffs between one large central system and multiple smalier systems? Should there be a forced air ducted system, a two-pipe fan coil system, or a combined water and air system? What space is avafiable for the equipment and distribution system? Assess the fire risk levels of various fuels. Understand the advantages and disadvantages of the various types of inechanical systems available. Then evaluate each of these systems in light of the preservation objectives established during the design phase of planning. Overview of HVAC Systems WATER SYSTEMS: Hydronic radiators, Fan coit, or radiant pipes Water systems are generally called hydronic and use a network of pipes to deliver water to hot water radiators, radiant pipes set in floors or fan coil cabinets which ca~ give both heating, and cooling. Boilers produce hot water or steam; chil~ers produce chilled water for use with fan coil units. Thermostats control the temperature by zone for radiators and radiant floors. Fan coil units have individual controls. Radiant floors provide quiet, even heat, but are not common. http://www. cr.nps.gov/hps/tps/briefs/brief24.htm 3/24/2003 22 Yreservauon t3neY 'L4: tieatmg, ventuaung, anA l;o0ling t1tSLOt7C tsuuu~ngs: rroo~e~ns aci... ragc o v. .~ Advantages: Piped systems are generally easier to install in historic buildings because the pipes are smaller than ductworic. Disadvantages: There is the risk, however, of hidden leaks in the wall or burst pipes in winter if boilers fail. Fan coil condensate pans can overflow if not properly maintained. Fan coils may be noisy. Hydronlc Radfators: Radiators or baseboard radiators are looped together and are usually set under windows or along perimeter walls. New boilers and circulating pumps can upgrade older systems. Most piping was cast iron although copper systems can be used if separately zoned. Modern cast iron baseboards and copper fin-tubes are available. Historic radiators can be reconditioned. Fan Coil Units: Fan coil systems use terminal cabinets in each room serviced by 2; 3, or 4 pipes approximately 11/2" each in diameter. A fan blows air over the coils which are serviced by hot or chilled water. Each fan coil cabinet can be individually controlled. Four-pipe fan coils can provide both heating and cooling all year long. Most piping is steel. Non-cabinet units may be concealed in closets or custom cabinetry, such as benches, can be built. CENTRAL AIR SYSTEMS The basic heating, ventilation and air conditioning (HVAC) system is all-air, single zone fan driven designed for low, medium or high pressure distribution. The system is composed of compressor drives, chillers, condensers, and furnace depending on whether the air is heated, chilled or both. Condensers, generally air cooled, are located outside. The ducts are sheet metal or flexible plastic and can be insulated. Fresh air can be circulated. Registers can be designed for ceilings, floors and walls. The system is controlled by thermostats; one per zone. Advantages: Ducted systems offer a high level of control of interior temperature, humidity, and filtration. Zoned units can be relatively smali and well concealed. Disadvantages: The damage from installing a ducted system without adequate space can be serious for a historic buiiding. Systems need constant balancing and can be noisy. Baslc HVAC: Most residential or small commercial systems will consist of a basic furnace with a cooling coil set in the unit and a refrigerant compressor or condenser located outside the building. Heating and cooling ductwork is usually shared. If sophisticated humidification and dehumidification is added to the basic NVAC system, a full ciimate control system results. This can often double the size of the equipment. Basic Heat Pump/Air System: The heat pump is a basic HVAC system as described above except for the method of generating hot and cold air. The system operates on the basic refrigeration cycle where latent heat is extracted from the ambient air and is used to evaporate refrigerant vapor under pressure. Functions of the condenser and evaporator http://www.cr.nps.gov/hps/tps/briefs/briefl4.htm ~ 3/24/2003 23 A fan coil unit in the basement is feeding controlled air to a primary space upstairs. Photo: CouKesy, Karen Sweeney, Frank lioyd WrigM Home & Studio. Preservabon Bnef'L4: Heahng, venutabng, ana Loonng tustonc tsuuamgs: rrooiems an... rage y oi io switch when heating is needed. Heat pumps, somewhat less efficient in cold c~imates, can be fitted with electric resistance coil. COMBINED AIR AND WATER SYSTEMS These systems are popular for restoration work because they combine the ease of instailation for the piped system with the performance and control of fhe ducted system. Smaller air handling units, not uniike fan coiis, may be located throughout a building with service from a central boiler and chiller. In many cases the water is delivered from a centrel plant which services a complex of buildings. This system overcomes the disadvantages of a central ducted system where there is not adequate horizontai or vertical runs for the ductwork. The equipment, being smaller, may also be quieter and cause less vibration. If only one air handler is being utilized for the building, it is possible to house all the equipment in a vault outside the buildi~g and send only conditioned air into the structure. Advantages: flexibility for installation using greater piping runs with shorter ducted runs; Air handlers can fit into small spaces. Disadvantages: piping areas may have undetected leaks; air handlers may be noisy. OTHER SYSTEM COMPONENTS Non-systems components should not be overlooked if they can make a buiiding more comfortable without causing damage to the historic resource or its collection. Advantages: components may provide acceptable levels of comfort without the need for an entire system. Disadvantages: Spot heating, coofing and fluxuations in humidity may harm sensitive collections or furnishings. If an integrated system is desirable, components may provide only a temporary soiution. Portsble Air Conditioning: Most individual air conditioners are set in windows or through exterior wails which can be visually as well as physicaily damaging to historic buiidings. Newer portabie air conditioners are available which sit in a room and exhaust directly to the exterior through a small slot created by a raised window sash. Pans: Fans should be considered in most properties to improve ventilation. Fans can be located in attics, at the top of stafrs, or in individual rooms. In moderate climates, fans may eliminate the need to instail central air systems. Dehumid/fiers: For houses without central air ha~dling systems, a dehumidifier can resolve problems in humid ciimates. Seasonai use of dehumidifiers can remove moisture from damp basements and reduce fungal growth. Heaters: Portable radiant heaters, such as those with water and glycol, may provide http://www.cr.nps.gov/hps/tps/briefs/briefl4.htm 3/24/2003 24 Installing a fan ~successtully conceaied here) for increased ventilafion can 6e a successtul low-tech substitute for air conditioning. Photo: Courtesy, Shelburne Village. temporary heat in buiidi~gs used infrequently or during systems breakdowns. Care should be taken not to create a fire hazard with improperly wired units. Designing the new system Tn designing a system, it is important to anticipate how it will be installed, how damage to historic materials can be minimized, and how visible the new mechanical system will be within the restored or rehabilitated spaces. Mechanical equipment space needs are often overwhelming; in some cases, it may be advantageous to look for locations outside of the building, including ground vauits, to house some of the equipment but only if it there is no adverse impact to the historic landscape or adjacent archeological resources. Various means for reducing the heating and cooiing loads (and thereby the size of the equipment) should be investigated. This might mean reducing slightly the comfort levels of the interior, increasing the number of climate control zones, or improving the energy efficiency of the bui~ding. The following activities are suggested during the design phase of the new system: 1. Establish specific criteria for the new or upgraded mechanical system. New systems should be installed with a minimum of damage to the resource and should be visually compatible with the architecture of the buiiding. They should be installed in a wey that is easy to service, maintain, and upgrade in the future. There should be safety and backup monitors in place if buildings have collections, computer rooms, storage vaults or special conditions that need monitoring. The new systems should work within the structural limits of the historic building. They should produce no undue vibration, no undue noise, no dust or mold, and no excess moisture that could damage the historic building materiats. If any equipment is to be located outside of the building, there should be no impact to the historic appearance of building or site, and there should be no impact on archeological resources. 2. Prioritize tha requirements for the new climate control system. The use of the building will determine the level of interior comfort and climate control. Sometimes, various temperature zones may safely be created within a historic building. This zoned approach may be appropriate for buildings with specialized coilections storage, fnr buiidings with mixed uses, or for large buildings with different external exposures, occupancy patterns, and delivery schedules for controlled air. Special archives, storage vaults or computer rooms may need a completely different climate controi from the rest of the building. Determine temperature and humidity levels for occupants and collections and ventilation requirements between differing zones. Establish if the system is to run 24 hours a day or only during opereting or business hours. Determine what.controls are optimum (manual, computer, preset automatic, or other). The size and location of the equipment to handle these different situations will ultimately affect the design of the overall system as well. 3. Mlnimize the impact of the new HVAC on the existing architecture. Design criteria for the new system should be based on the type of architecture of the historic resource. Consideration should be given as to whether or not the delivery system is visible or hidden. Utilitarian and industrial spaces may be capab~e of accepting a more visible and functional system. More formal, ornate spaces which may be http://www. cr.nps.gov/hps/tps/briefs/brief24.htm 3l24/2003 25 YreservaUOn t3neY 14: tleanng, Venuiaung, ana Looimg tustonc nuuomgs: rroolems ... rage i i oi io part of an interpretive program may require a less visible or disguised system. A ducted system shouid be installed without ripping into or boxing out large sections of floors, wails, or ceilings. A wet pipe system should be installed so that hidden leaks will not damage important decorative finishes. In each case, not only the type ~f system (air, water, combination), but its distribution (duct, pipe) and delivery appearance (grilies, cabinets, or registers) must be evaluated. It may be necessary to use a combination of different systems in order to preserve the historic building. Existing chases should be reused whenever possible. :~y This radiator would be identi(ed as a 4. Balance uantitative re uirements and significantelementoftheinterior.lnany 4 4 vrork to upgrade the mechanical system, it preservation objectives. The ideal system may not wou~d be retained and preservee, even if be achievable for each historic resource due to cost, ^on-functioning. Photo: NPS files. space limitations, code requiremeMS, or other factors beyond the owner's control. However, significant historic spaces, finishes, and features can be preserved in almost every case, even give~ these limitations. For example, if some ceiiing areas must be slightly lowered to accommodate ductwork or piping, these should be in secondary areas away from decorative ceilings or tall windows. If modern fan coil terminal units are to be visible in historic spaces, consideration should be gfven to custom designing the cabinets or to using smaller units in more locations to diminish their impact. If grilles and registers are to be located in significant spaces, they should be designed to work within the geometry or placement of decorative elements. All new elements, such as ducts, registers, pipe-runs, and mechanical equipment shouid be Installed in a reversibie manner to be removed in the future without further damage to the building. Systems Performance and Maintenance Once the system is installed, it wili require routine maintenance and balancing Yo ensure that the proper performance levels are achieved. In some cases, extremely sophisticated, computerized systems have been developed to control interior climates, but these still need monitoring by trained staff. If coliection exhibits and archival storage are important to the resource, the climate control system will require constant monitoring and tuning. Backup systems are also needed to prevent damage when the main system is.not working. The owner, manager, or chief of maintenance should be aware of all aspects of the new climate controi system and have a plan of action before it is installed. A sprinkler system is unobtrusively placed behind a false cornice at [he end of a corridor. Photo: NPS Regular training sessions on operating~ fies. monitoring, and maintaining the new system should be held for both curatorial and building maintenance staff. If there are curatorial reasons to maintain constant temperature or humidity levels, only individuals thoroughly trained. in how the HVAC systems operates should be able to adjust thermostats. III- informed and haphazard attempts to adjust comfort levels, or to save energy over weekends and~holidays, can cause great damage. http://www. cr.nps.gov/hps/tps/briefs/briefl4.htm 3/24/2003 26 neanng, vennianng, anu ~c~onng HVAC Do's and Don'ts DO's: . Use shutters, operable windows, porches, curtains, awnings, shade trees and other historically appropriate nonmechanicai features of historic buildings to reduce the heating and cooling loads. Consider adding sensitively designed storm windows to existing historic windows. . Retain or upgrade existing mechanical systems whenever possible: for example, reuse radiator systems with new boilers, upgrade ventilation within the bui~ding, install proper thermostats or humidistats. • Improve energy e~ciency of existing buildings by installing insulation in attics and basements. Add insulation and vapor barriers to exterior walls only when it can be done without further damage to the resource. • In major spaces, retain decorative elements of the historic system whenever possible. This includes switch-plates, grilles and radiators. Be creative in adapting these features to work within the new or upgraded system. . Use space in existing chases, closets or shafts for new distribution systems. • Design climate control systems that are compatible with the architecture of the building: hidden system for formal spaces, more exposed systems possible in industrial or secondary spaces. In formal areas, avoid standard commercial registers and use custom slot registers or other less intrusive grilles. . Size the system to work within the physical constraints of the building. Use multi- zoned smaller units in conjunction with existing vertical shaRs, such as stacked closets, or consider locating equipment in vaults underground, if possible. . Provide adequate ventilation to the mechanical rooms as well as to the entire building. Selectively install air intake grilles in less visible basement, attic, or rear areas. • Maintain appropriate temperature and without accelerating the deterioration regular monitoring schedules. humidity levels to meet requirements ~f the historic building materials. Set up • Design the system for maintenance access and for future systems replacement. • For highly significant buildings, install safety monitors and backup features, such as double pans, moisture detectors, lined chases, and battery packs to avoid or detect leaks and other damage from system failures. • Have a regular maintenance program to extend equipment life and to ensure proper performance. http://www. cr.nps.gov/hpsltps/briefs/brief24.htm 3/24/2003 27 Preservation BneY 24: Hesbng, Venulahng, antl t;oolmg tlistonc tsuuumgs: rromems ... rage is ot io • Train staff to monitor the operation of equipment and to act knowledgeably in emergencies or breakdowns. • Have an emergency plan for both the building and any curatorial collections in case of serious maifunctions or breakdowns. DON'TS: • Don't install a new system if you don'L need it. • Don't switch to a new type of system (e.g. forced air) unless there (s sufficient space for the new system or an appropriate place to put it. . Don't over-design a new system. Don't add air conditioning or climate control if they are not absolutely necessary. • Don't cut exterior historic buifding wails to add through-wall heating and air conditioning units. These are visually disfiguring, they destroy historic fabric, and condensation runoff from such units can further damage historic materials. . Don't damage historic finishes, mask historic features, or alter historic spaces when installing new systems. • Don't drop ceilings or bulkheads across window openings. • Don't remove repairable historic windows or replace them with inappropriately designed thermal windows. . Don't seal operable windows, unless part of a museum where air pollutants and dust are being controlled. • Don't place condensers, sofar panels, chimney stacks, vents or other equipment on visible portio~s of roofs or at significant tocations on the site. . Don't overload the building structure with the weight of new equipment, particularly in the attic. • Don't place stress on historic building materials through the vibrations of the new equipment. ~ . Don't allow condensation on windows or within walls to rot or spall adjacent historic buiiding materials. Maintenance staff should learn how to operate, monitor, and maintain the mechanical equipment. They must know where the mafntenance manuals are kept. Routine maintenance schedules must be developed for changing and cleaning filters, vents, and condensate pans to control fungus, mold, and other organisms that are dangerous to health. Such growths can harm both inhabitants and equipment. (In piped systems, for example, molds in condensate pans can block drainage lines and cause an overflow to http:!lwww. cr. nps.gov/hps/tps/briefs/briefl4.htm 3/24/2003 28 leak onto finished surfaces). Maintenance staff should aiso be able to monitor the appropriate gauges, dials, and thermographs. Staff must be trained to intervene in emergencies, to know where the master controls are, and whom to call in an emergency. As new personnel are hired, they wiil also require maintenance training. In addition to regular cyclical maintenance, thorough inspections should be undertaken from time to time to evaluate the continued performance of the cfimate control system. As the system ages, parts are likely to fail, and signs of trouble may appear. Inadequately ventilated areas may smeil musty. Wall surFaces may show staining, wet patches, bubbling or other signs of moisture damage. Routine tests for air quality, humidity, and temperature shouid indicate if the system is performing properly. If there. is damage as a result of the new system, it should be repaired immedfately and then closely monitored to ensure complete repair. Equipment must 6e accessibls for maintenance and should be visible for easy inspection. Moreover, since mechanical systems last only 15-30 years, the system itself must be "reversible." That is, the system must be installed in such a way that later removal will not damage the building. In addition to servicing, the backup monitors that signai . malfunctioning equfpment must be routinely checked, adjusted, and maintained. Checklists should be developed to ensure that all aspects of routine maintenance are completed and that data is reported to the building manager. Conclusion The successful integration of new systems in historic buildings can be challenging. Meeting modern HVAC requirements for human comfort or installing controlled climates for museum collections or for the operetion of complex computer equipment can result in both visual and physical damage to historic resources. Owners of historic buildings must be aware that the final result wili involve balancing multiple needs; no perfect heating, ventilating, and air co~ditioning system exists. In undertaking changes to historic buildings, it is best to have the advice and input of trained professionals who can: . assess the condition of the historic building, . evaluate the significant elements that should be preserved or reused, • prioritize the preservation objectives, . understand the impact of new interior climate conditions on historic materials • integrete preservation with mechanical and code requirements, . maximize the advantages of various new or upgraded mechanical systems, , • understand the visuai and physical impact of verious installations, . identify maintenance and monitoring requirements for new or upgraded systems, and • plan for the future removal or repiacement of the system. Too often the presumed climate needs of the occupants or collections can be detrimental to the long-term preservation of the building. With a careful balance between the preservation needs of the building and the interior temperature and humidity needs of the occupants, a successful project can result. http://www.cr.nps.gov/hps/tps/briefs/brief24.htm 3/24/2003 29 Preservation Brief 24: Heating, Ventilating, and Cooling Historic Buildings: Yroblems ... Page I S of 16 , Bibliography Banham, Reyner. The Architecture of the Well-Tempered Envlronment. London: The Architectural Press, 1969. Burns, John A., AIA. Energy Conserving Features Inherent in Older Homes. Washington: U.S. Department of Housing and Urban Development and U.S. Department of the Interior, 1982. ' Cowan, Henry ]. Science and Suilding: Structural and Environmentai Design in the Nineteenth and Twentieth Centuries. New York: John Wifey & Sons, 1978. Ferguson, Eugene S. "An Historical Sketch of Central Heating: 1800-1860," in Building EarlyAmerica (Charles Peterson, editor) Philadelphia: Chilton Book Co., 1976. Fitch, James Marston. American Building: The Envlronmenta/ Forres That Shape It. Boston: Houghton-Mifflin Co., 1972. Giedion, Siegfried. Mechanization Takes Command--a Contribution to Anonymous History. New York: Oxford University Press, 1948. Merritt, Frederick S. Bui/ding Engineering and Systems Design. New York: Van Nostrand Reinhold Co, 1979. Smith, Baird M. Preservation Briefs 3: Conserving Energy in Historic Buildings. Washington, DC: U.S. Department of the Interior, 1978. Turberg, Edward. A History ofAmerican Building Techno%gy. Durham: Durham Technical Institute, 1981. Acknowledgements The author gratefully acknowiedges the invaluable assistance of Mlchael C. Henry, P.E., AIA, In khe development and technical editing of this Preservalion Brief. 7eehnical review was also provided by Ernest A. Conrad, P.E. Thanks is also given to staff members of the National Park Serviee Cultural Rasources Programs, fnclud(ng Tom Keohan and Catherlne Colby, Rocky Mountain Region; Michael Crowe, Western Repion; Mark Chavez, Midwest Repion; Randall J. Biallas, AIA, Chief, Park H4storic Architecturo Dlvision, and George A. Thorsen, Historical Architect, penver Service Center. Speclal thanks is aiso given to Miehael J. Auer of Technical Preservation Services for hIs editorial assistance in preparinp this paper and Tim Buehner for his assistance with the illustrations. Wsshinpton, D.C. Octobe~, 1991 Home page logo: Historic boiler in functioning condition. Photo: NPS files. This publication has 6een prepared pursuant to the Nationa! Historlc Preservatlon Act of i966, as amended, which directs the Secretary of the Interior to develop and make available information concerning historic properties. Technica! Preservation Services (TPS), Heritage Preservation Services Division, National Park Service prepares standards, guidelines, and other. educationa/ materials on responslb/e historic preservation treatments to a broad public. http://www.cr.nps.gov/hps/tps/briefs/brief24.htm 3/24/2003 30 ~ Date Sub District: Applican Mobile Phone: Relationsltip to projeet (e.g., arcliicect, contractor): Applicant's Mailmg Address: L~~ j~~' Property;owner's uame: ~~ ~d ,,:, *Property owner's~~fu11 address: 3~ - # 0 Day-Time *Tl~is information is required in order to fully process tliis application. ~ ~ ti..-,; . ~. To assist us in reviewing your project, please provide a project description.in`the space provided Uelow. Include all of fhe exterior alterations proposed for the property. Please bring the completed application with you to your first design review meeting. If you have questions, or to schedule an appointment for review, please contact Neil Holthouser at 303-441-4293, We look forward to warking with you on your proposaCl PROJECT DESCRIPTION Please list all exteriar alterations proposed for the property. La~e, ~~~-" u,~.~ TYPE OF ALTERATION Please check all that apply. New Addition _New Garage** _Demolition** _Window(s) _Door _Fence _ Fax: ~303~ ~~' ~ ~ 3 l~V'G1nI~cJ~ _12oof Repair _Deck _Dormer(s) _Skylight(s) _Paiut _Porch Repuired: ~_Lot size (in square feet) ~_Total existing square feet additional square feet ~1(~Existing height ~_Proposed height _New Roof Other (please specify): ~ D e~pll~?M`~D'r ~.1141~ **Rcquires a puUlic hearing 10.02-LACappl Page 1 of 2 t~ri.lfi}n.+Ci4 r~ ~ v ,q,~~ ~~'~~ ~ J ,~ . 4 ~q 'S . ~ ri~:. i~,~~i'.S~i~ ,T'~, 0'1~~ f~~ ~ '' . - ' d P' f ~ fi ~ ~+~; £of~~"r~Y'~~<'~ ~~'~. ~~ . ~.. ; ., S'.Y4 ~ V F 1 j y./ q C x N' i ' ~ ~ i n~~`~~~N .~~~~ 5f x~ S~ h~~+~y ~% Bv+,S': ~ ~ N. WIZ(~tLO BYLRg t0 YOllP R6VLCW ~ ~ z,;. tt , "~.. ~'r°' , ~ ~,~z ,.~C_~'<, ~ Please bring this completed applicarion form and the materials listed below to the design review meeting. To make the most of your design review, it must illustrate what you have in mind very clearly and accurately. Final approval cannot be given without the required documentation listed below: The followin~ documentation is reauired to initiate'concentual' revicw bv the Desieu Review Committee• ~ ,~4 Photographs (photos of existing building and sunounding context) : _Drawings (skctches or scaled drawings of the proposal) The followine documentaYion is reauired for final'rev-'ew alud approval ,,~~ ,, ~ ~ n ~~ ~e , ~ ~ ~bvu~ ~ ~ s ~ Soaledsit¢plans : ' ~~ ` ~'~ ~ "~~'~'~ ~ ~ - . ' ~_ ' ~1 y i~ 4 `~ ;;~~n~~~ ~' ,~ _Elevations (usually 1/4 1 `soale)~ ~ ~ w, ~ ,~, ~~ ' _Matcrials (brick/stone samples) y' ;~ "~~ ` Colors (paintlstain color'chip) ~ ~ °, d~'~ ~~~,~~ •. ~ ~ ~ ~ _Photographs (photos of existing building al( sides and surrounding contex,t) ~,,:. .. _Manufactuier's/catalogue "tear" sheet '~ ' `1` '' , _For fences, please bring drawings to scale showing dimensions, including spacing between rails. It is also helpful if vou provide: _Building sections _Floor plans COMMITTEE COMAIGNTS ABOUT'CIIC PROPOSAL: . ~ TStudy model (addirions) NEXT STGPS: PUBL[C HEAR[NG? YES NO The Design Review Committee cannot deny an alteration application, however, any one Committee member can require a full-board hearing. 10.02-LACappl Page 2 of 2 ~ MAIN LEVEL PLAN ~ro• .r-o• ~ poSS~~ COl^~G~~~kV l6 C.a~7 0l15 C~~~e ~ ~ ; FROM :ALICE 7HOMHS FRX N0. :7135241045 :. ~~FMar. 09 2003 10:05PM P2 ;~h ,>~... ,, A1ice Crawford Thomas ' 3102 Reba D,nve Houston, Texas 77019 March 9, 2003 ~ Dear Gtounds Committee: I am the owner of Cotta~e #20 which was built in the early 1940s by my great gtandmother. I am a foittth generation Chautauquan and my children and grandchildren are summer visiton to ihe cottage. Thi~ wivZer, we begart inteniorrenovations to upd~ the wuin~ ~tiuct~ue, aud piping co meet piesent day cbde. All of the ct~anges }rave been approved by I,an~trs~azks and/or t~ave been ckscussad with St~.we Wa~ans: As pazt of dus Pm.ject, we would Iitce to remove the six wiindaw air coadidoniug tmits 8nd replace them with a small, low decibel candenser for a czmral air and l~arit~'system. The cm~denux wwild be plaCed ia an approvad Iocation The six window imits weze added some 10 to IS yeazs ago w mitigate the discomfort resulting from Bouida's icxreasingly wemi sumnte~s and the westem expas~uc of ow cottage. Jmpartantly, the use o£ihe front scr~cnad ~ on the east side has nat beezc affeaed by the'cvindow units, ncrt would it be aS'edad by the addition ofa cenual sir system 'UVhite considering the cottcept of air conditioning condensers on the Chautauqua grounds, please recall that C6autauqua's own Missions House has two outside condensers. Please also consider the £act that our single condenser would be considerable less obt[usive attd make less noise thsn the existing window units. For generations, we have bee~ Ieaving Texas each summer to enjoy Cotorado's moixntains and our Chautauqua &iends. We want to encourage the next generation of our famiJy to condnue this tradition in pieasanc and comfortable conditions ~ank you for you time and considaration. Please call me at 713 524-2744 or email me at ACT524{c"~aol.com if I cun answer any specifie quesfioas regarding ovr cutrent work on Cottage #20. Sincerely, `h~~ ~d e~.~.. N, ~ ~ ., ,. t~,~,.~ . .Alice crawfora Thonnas C~ ~ 20 LE6AL DESGRIPTION~ Gottage ~-20 Ghautauq,va Park Block 'id, Lot 13 5outh I/2 lot 14 . ........ .. .. . ...... ._ .. . . . .,. ,.._. . ._ = ~ 4 ^ Q fl ~] o , ~l . o ~ o ~ ~ ~ ~ F~ ~ ~ ~ ~ ~ ~ ~ ~ o ~ G'~ 4 ; ~] a ° ~ Q ~ ~ £3 ~ ' a ~ ~ ~ ~ - ~ ~ ~ , : :~,,... , ~ . ~.....W . pe.d ~ ~ ~' i '~ y ~° ~} ~ ~ ° a ~ ' ~ Q : ( ~ u n ' ~ O ~~ ~~ O ~ \, ' 3 °ro ~ 0 0 ~ m ~ ~ t U 0 60 700 W F~~t j o ~ , 1: ~ ~, ,, _:..... ~fi~,.- ~ ~~ ~ ~ ~ Chautauqua Park ,,. 7 ~ ~U ~W F- -~i~--~- - ~_ b U ~~ ~a P~~ ~ ~ Q d~) ~4 f P-v'9 ~~ ~ ~H F--~-~ C/!1 PQ'~ ~ b i ~ ~/~ ~ ~~ ~ ~ b `~•;~~~i: . ~~ Historic District ' ! ~ ~ ... . .__.._ ' -~--d~--a ~,~ ~ ~ )I~ ' i ~ w ~ ' v E !i ~ ........... ... ..: .... .. . . . .... _ ... ~ ~ o .... ___ . ., ,, -_ /~ Si~e/Location Plan _ C. fl~ e . .~„,.~, ~ ,.~ , ~ N [7v~ M E"~ ~O aU .- ~J~`'' ' !i ~t :"" J~`/ ~ r ;- ,'r ~~~.- ~r ~' ~ ~~//i~% ~ j' ' .,-~ '/~.; .. ,. ~. ; ~,.,/, ,% ~ ,% - i - ri~` • ~ ,; , ~' ~ ~ , / . 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