05/09/19 Jennifer Cappeto, Landmark Preservation Manager Community Planning and Development – City and County of Denver RE: LPC application for 1019 York Street – Boettcher Memorial Center Renovation As you know, our first application to the Landmark Preservation Commission was denied on 05/07/19, due to concerns of the Commission that a proposed louver on the east side of the building would be detrimental to the historic fabric of the building. This louver served an economizer for our HVAC system, and was required by the new Energy Code, 2015 IECC: C403.3.3. As suggested by the Commission, we considered other locations for the louver, but are significantly restricted in where we can run the economizer’s ductwork given the bulky nature of the concrete structure within the interior of the building, and the low ceilings. Also, finding a different location for the louver on an exterior wall that would be acceptable to the commission seemed unlikely. The other suggestion of creating a window well louver was estimated to be cost-prohibitive due water mitigation requirements and its more extensive structural implications. So now we plan to pursue an exemption in the IECC for historic buildings, C501.6, which will eliminate the requirement for an economizer as well as any new louver on the exterior of the building. This will also allow us to remove two new exhaust fans on the roof, which served the economizer. One of them was within the Landmark designation area, and one was outside of it. We believe this is the best path forward and faithfully addresses the Commission’s concerns over the new louver. We have updated our application packet by removing the louver and its associated exhaust fans. The application is now limited to the two remaining exhaust fans, and the work we plan to do to remove the exterior RTU and its mechanical screen, along with replacing the windows that are currently used for duct penetrations with matching windows that the Gardens has in storage. Respectfully Submitted, David Daniel Patrick Lee Micah Holroyd Davis Partnership Architects
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05/09/19 Jennifer Cappeto, Landmark Preservation Manager ... · Landmark Preservation staff would recommend that the project be exempt from this section of the IECC so as not to threaten,
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05/09/19
Jennifer Cappeto, Landmark Preservation Manager
Community Planning and Development – City and County of Denver
RE: LPC application for 1019 York Street – Boettcher Memorial Center Renovation
As you know, our first application to the Landmark Preservation Commission was
denied on 05/07/19, due to concerns of the Commission that a proposed louver
on the east side of the building would be detrimental to the historic fabric of the
building.
This louver served an economizer for our HVAC system, and was required by the
new Energy Code, 2015 IECC: C403.3.3. As suggested by the Commission, we
considered other locations for the louver, but are significantly restricted in where
we can run the economizer’s ductwork given the bulky nature of the concrete
structure within the interior of the building, and the low ceilings. Also, finding a
different location for the louver on an exterior wall that would be acceptable to
the commission seemed unlikely. The other suggestion of creating a window well
louver was estimated to be cost-prohibitive due water mitigation requirements
and its more extensive structural implications.
So now we plan to pursue an exemption in the IECC for historic buildings, C501.6,
which will eliminate the requirement for an economizer as well as any new louver
on the exterior of the building. This will also allow us to remove two new exhaust
fans on the roof, which served the economizer. One of them was within the
Landmark designation area, and one was outside of it. We believe this is the best
path forward and faithfully addresses the Commission’s concerns over the new
louver.
We have updated our application packet by removing the louver and its
associated exhaust fans. The application is now limited to the two remaining
exhaust fans, and the work we plan to do to remove the exterior RTU and its
mechanical screen, along with replacing the windows that are currently used for
duct penetrations with matching windows that the Gardens has in storage.
Respectfully Submitted,
David Daniel
Patrick Lee
Micah Holroyd
Davis Partnership Architects
Landmark Preservation Community Planning and Development
201 W. Colfax Ave., Dept. 205 | Denver, CO 80202 www.denvergov.org/landmark
p. 720.865.2709
May 9, 2019 Scott Prisco Building Official City and County of Denver 201 W. Colfax Avenue Denver, CO 80202 Subject: Energy Code Exemption for 1019 York Street Dear Scott: The property located at 1019 York Street at the Denver Botanic Gardens is an individual landmark structure known as the Boettcher Memorial Center designated in 1974. As such, the property is considered a historic building per the 2015 International Energy Conservation Code. Section C501.6 of the 2016 Denver Amendments to the International Energy Conservation Code states:
No provisions of this code relating to the construction, repair, alteration, restoration and movement of structures, and change of occupancy shall be mandatory for historic buildings provided that one of the following applies: c. The local historic preservation authority having jurisdiction provides documentation to the code official with a finding that compliance with that provision would be in conflict with locally adopted historic preservation policies, standards, and guidelines, outlining the specific provisions that are in conflict and how compliance would threaten, degrade or destroy the historic character or features, of the historic form, materials or function of the building.
Denver Landmark Preservation is the local historic preservation authority for the City and City and County of Denver, and we adopted the Secretary of the Interior’s Standards for Rehabilitation as the guiding principles for all historic preservation work in the city; the Design Guidelines for Denver Landmark Structures and Districts are based on the Secretary of the Interior’s Standards. To comply with Section C403.3.3 and C403.3.3.1 of the 2015 IECC, the project team originally proposed to install an air economizer in the building. This would entail installing louvers on the east elevation of the building by cutting through the poured concrete face of the building. On May 7, 2019, the applicant presented the project to the Landmark Preservation Commission, which voted to deny the application. The Commission expressed concern that cutting out a portion of the concrete face of the building would destroy the historic form and fabric of this significant Modernist building. In their motion to deny the application, they cited two design guidelines: guideline 2.60 “Place mechanical, utility and communications equipment to minimize visual impacts on a historic building”; and guideline 2.61 “Install communications, utility and mechanical equipment to minimize damage to historic building fabric.” Following the Commission’s denial of the application, the applicant requests an exemption from Sections C403.3.3 and C403.3.3.1 of the 2015 IECC to allow them not to install air economizers at the building. Landmark Preservation staff would recommend that the project be exempt from this section of the IECC so as not to threaten, degrade or destroy the historic form and fabric of the Boettcher Memorial Center at 1019 York Street. Sincerely, Jennifer Cappeto On behalf of the Landmark Preservation Commission City and County of Denver
DATE:PROJECT NUMBER:COPYRIGHT - DAVIS PARTNERSHIP, P.C.
15523.10
DENVER BOTANIC GARDENS - BOETTCHER MEMORIAL CENTER
RENOVATION
Extent of Landmark Designation 04/19/19
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Site Context
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Extent of Landmark Designation within the Boettcher Memorial Center 1019 York Street, Denver, CO 80206
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1
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Polygon
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AERIAL IMAGE OF BOTANIC GARDENS BUILDINGS ALONG YORK STREET - PLEASE EXCUSE DISTORTION - IMAGE FROM GOOGLE EARTH
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MAIN ENTRANCE TO DENVER BOTANIC GARDENS
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YORK STREET
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Arrow
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Arrow
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Dimension
ELEVATION OF EXSTING BIULDING SHOWN IN DRAWINGS ON FOLLOWING SHEETS
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LOCATION OF EXISTING EXTERIOR MECH UNIT AND SCREEN TO BE REMOVED
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VIEW 2
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VIEW 4+5
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2
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AREA OF EXISTING MECH SCREEN AND EQUIPMENT TO BE REMOVED
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VIEW 2 FROM YORK STREET
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3
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EXISTING MECH SCREEN TO BE REMOVED
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VIEW 4 - INSIDE THE GARDENS
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4
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EXISTING DUCTS RUNNING THROUGH WINDOW OPENINGS. TO BE REPLACED WITH MATCHING OPERABLE WINDOWS THAT ARE CURRENTLY STORED ON SITE
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EXISTING MECH SCREEN AND EQUIPMENT TO BE REMOVED
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VIEW 5 - INSIDE THE GARDENS
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1
7
1
7
35' - 9 3/8"
NEW EXHAUST FAN (EF-1)REPLACING EXISTING
EXISTING DUCTWORK TO REMAIN
MAIN ENTRANCE
EXISTING RTUs TO REMAIN
NEW EXHAUST FAN (EF-2)ON NON-LANDMARK DESIGNATED ROOF
DATE:PROJECT NUMBER:COPYRIGHT - DAVIS PARTNERSHIP, P.C.
15523.10
DENVER BOTANIC GARDENS - BOETTCHER MEMORIAL CENTERRENOVATION
Roof Plan 05/09/19
1" = 20'-0"1BOETTCHER - MECHANICAL ROOF PLAN
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EF-1
DATE:PROJECT NUMBER:COPYRIGHT - DAVIS PARTNERSHIP, P.C.
15523.10
DENVER BOTANIC GARDENS - BOETTCHER MEMORIAL CENTER
RENOVATION
Building Section 05/09/19
1/16" = 1'-0"1EAST - WEST BUILDING SECTION
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YORK STREET
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Replacing these windows currently used as duct penetrations.
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EXISTING WOOD MECH SCREEN TO BE REMOVED
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1'-8"
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3'-10"
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BUILDING ELEVATION FACING YORK STREET - WITH PROPOSED MODIFICATIONS
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BOETTCHER - L1109' - 7 1/32"
BOETTCHER - LL99' - 7 1/32"
0
3' -
10
1/2
"4
' -
10
1/2
"
12
2
12
3
INSTALL SALVAGED
ALUMINUM WINDOWS
FROM STORAGE THAT
MATCH EXISTING
WINDOWS ON THIS
ELEVATION
1' -
6"
3 1/2"
1' - 8"
0
SET SALVAGED WINDOW BACK FROM EXTERIOR
FACE OF CONCRETE WALL TO MATCH SETBACK OF
OTHER EXISTING WINDOWS
EXTERIOR FACE OF EXISTING CONCRETE
WALL BEYOND SECTION CUT
3 1/2"
0
SET SALVAGED WINDOW BACK FROM EXTERIOR
FACE OF CONCRETE WALL TO MATCH SETBACK OF
OTHER EXISTING WINDOWS
EXTERIOR FACE OF EXISTING CONCRETE
WALL BEYOND SECTION CUT
3 1/2"
1' - 8"
EXTERIOR FACE OF
EXISTING CONCRETE
WALL CUT BY
SECTION
DATE:PROJECT NUMBER:COPYRIGHT - DAVIS PARTNERSHIP, P.C.
15523.10
DENVER BOTANIC GARDENS - BOETTCHER MEMORIAL CENTER
RENOVATIONWall Section at New Windows inExisting Opening 04/19/19
1/2" = 1'-0"1
Wall Section at New Windows in ExistingOpenings
1 1/2" = 1'-0"2Window Head
1 1/2" = 1'-0"3Window Sill
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Existing window - cardboard behind glass will be removed
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OVERALL HEIGHT MAY BE GREATER DEPENDING ON MOTOR.
19.00 SQ
1.75
23.70
Ø 24.40
35.70
(12.00)
Model: G-103-VGDirect Drive Centrifugal Roof Exhaust Fan
DimensionalQuantity 1
Weight w/o Acc's (lb) 35
Weight w/ Acc's (lb) 52Roof Opening (in.) 14.5 x 14.5
PerformanceRequested Volume (CFM) 1,000
Actual Volume (CFM) 1,000
Total External SP (in. wg) 0.75
Fan RPM 1709
Operating Power (hp) 0.23
Elevation (ft) 5,430
Airstream Temp.(F) 70
Air Density (lb/ft3) 0.061
Tip Speed (ft/min) 4,978Static Eff. (%) 50
MotorMotor Mounted Yes
Size (hp) 1/4
Voltage/Cycle/Phase 115/60/1
Enclosure ODP
Motor RPM 1725
Windings 1FLA (Amps) 2.85
Notes:All dimensions shown are in units of in.*NEC FLA - based on tables 430.248 or 430.250 ofNational Electrical Code 2014. Actual motor FLA may vary,for sizing thermal overload, consult factory.LwA - A weighted sound power level, based on ANSI S1.4dBA - A weighted sound pressure level, based on 11.5 dBattenuation per Octave band at 5 ft - dBA levels are notlicensed by AMCA InternationalSones - calculated using AMCA 301 at 5 ft
Sound Power by Octave BandSoundData 62.5 125 250 500 1000 2000 4000 8000 LwA dBA Sones