Jon Biggs From: Sent : To: Cc: Subject: Atta ch me nts: Hi Jon, Brett Bail ey <brett.bail [email protected]> Monday, March 13, 2017 6:42 PM Jon Biggs David Kornfield CT Zoning Heig ht Li mits - PTC Meeting Pub li c Heari ng Ma rch 16, 2017 Ko ne-MonoSpace500_34115.pdf; 0ti s-G2S- PDF -P14.pdf; Thysse n Krupp-WR039 _S YN ERGY _ SE1SMIC_5000H @200_ DS_SE.pdf As you may be are aware, we are working on the construction drawings for the project at 4880 El Cam in o Real in Los Altos (4880). One of the items we are worki ng to resolve is the issue of the allowable roof structure height on the roof top. On this project, we researched several elevator manufacturer in an effort to find the shortest elevator structure possi bl e. Machine-room-less (MRL) traction elevators have become the common elevator type for projects of this scale so the MRL elevators we looked at were all based on the followi ng criteria: nine foot cab (eight foot doors), 5000 lbs. and a speed of approximately 200 FPM. The lowest shaft height was an elevator man uf actured by Kone. The Kone elevator has an overhead clearance of 15' -3" above the roof. Compa ri ng elevators of similar type and size, Otis has an elevator with an eight foot cab with an overhead clearance of 16'-1 above the roof (15'-1 "- 'AA' dimension as noted + eight inch hoist beam + 4" clea rance- see section). For a comparable nine foot cab (They only offer a 9'-9" cab), the overhead clearance above the roof would be an additional two feet, or 18'-1" above the roof. Thyssen Krupp's comparable elevator has an overhead clea rance of 16'-4" above the roof fo r an eight foot cab with an overhead clearance of 17'-4" for a comparable nin e foot cab. We also looked at Schindler and Fujitec, but they did not have a comparable elevator for use in California at the ti me. I am sendi ng you a sect ion of each of the manufacturer's data obtained from their individual websites. As you can see, each elevator varies in its dimensions and depending on the capacity, elevator speed, cab size and number of stops, etc., its ove rh ead clearance requirements. It is wo rt h reiterating, however, that the elevator for the 4880 project-a 5000 lb., nine foot cab, 200 FPM elevator- will just work in under 15'-6". It will require that we design the roof to within the remaini ng three inches (15'-6" minus 15'-3"). It can be done, but the roof will be unconventiona l. According to this week's Agenda Report Summary for the PTC meeting this Thursday, the recommendation is to revise the allowable roof structure height to 15 feet six inches. Considering the fact that only one elevator on the market serving a rooftop can achieve this, is it reasonable that this maximum allowable height should be higher than 15'-6" and/or an allowance provided for tall er structures under certain conditions? Based on the data presented above, do you th ink an adjustment could be made to allow for a taller roof structure of, say, 17 feet as a baseline with an additional height allowance based on the distance the roof structure is set back from the edge of the roof (where th e elevator would not be as visible from below)? In think ing about your recommendati on , I just wanted to share my two cents on the issue with the hope that the above information is considered and is usefu l. I appreciate your time, Jon. Sincerely, BRETT N. BAILEY AIA Associate / Senior Architect C I ARCHITECTURE I PLAN NING 5865 Owens Drive Pleasanton. Ca li fornia 94588 USA
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Transcript
Jon Biggs
From: Sent: To: Cc: Subject: Attachments:
Hi Jon,
Brett Bailey <[email protected]> Monday, March 13, 2017 6:42 PM Jon Biggs David Kornfield
CT Zoning Height Limits - PTC Meeting Public Hearing March 16, 2017 Kone-MonoSpace500_34115.pdf; 0tis-G2S-PDF-P14.pdf; Thyssen Krupp-WR039 _SYN ERGY _SE1SMIC_5000H @200_DS_SE.pdf
As you may be are aware, we are working on the construction drawings for the project at 4880 El Camino Real in Los Altos (4880). One of the items we are working to resolve is the issue of the allowable roof structure height on the roof top. On this project, we researched several elevator manufacturer in an effort to find the shortest elevator structure possible. Machine-room-less (MRL) traction elevators have become the common elevator type for projects of this scale so the MRL elevators we looked at were all based on the following criteria: nine foot cab (eight foot doors), 5000 lbs. and a speed of approximately 200 FPM. The lowest shaft height was an elevator manufactured by Kone.
The Kone elevator has an overhead clearance of 15'-3" above the roof.
Comparing elevators of similar type and size, Otis has an elevator with an eight foot cab with an overhead clearance of 16'-1 above the roof (15'-1 "- 'AA' dimension as noted + eight inch hoist beam + 4" clearance- see section). For a comparable nine foot cab (They only offer a 9'-9" cab), the overhead clearance above the roof would be an additional two feet, or 18'-1 " above the roof.
Thyssen Krupp's comparable elevator has an overhead clearance of 16'-4" above the roof for an eight foot cab with an overhead clearance of 17'-4" for a comparable nine foot cab.
We also looked at Schindler and Fujitec, but they did not have a comparable elevator for use in California at the time.
I am sending you a section of each of the manufacturer's data obtained from their individual websites. As you can see, each elevator varies in its dimensions and depending on the capacity, elevator speed, cab size and number of stops, etc., its overhead clearance requirements. It is worth reiterating, however, that the elevator for the 4880 project-a 5000 lb., nine foot cab, 200 FPM elevator- will just work in under 15'-6". It will require that we design the roof to within the remaining three inches (15'-6" minus 15'-3"). It can be done, but the roof will be unconventional.
According to this week's Agenda Report Summary for the PTC meeting this Thursday, the recommendation is to revise the allowable roof structure height to 15 feet six inches. Considering the fact that only one elevator on the market serving a rooftop can achieve this, is it reasonable that this maximum allowable height should be higher than 15'-6" and/or an allowance provided for taller structures under certain conditions? Based on the data presented above, do you think an adjustment could be made to allow for a taller roof structure of, say, 17 feet as a baseline with an additional height allowance based on the distance the roof structure is set back from the edge of the roof (where the elevator wou ld not be as visible from below)?
In thinking about your recommendation, I just wanted to share my two cents on the issue with the hope that the above information is considered and is useful.
I appreciate your time, Jon.
Sincerely,
BRETT N. BAILEY AIA Associate / Senior Architect
C I ARCHITECTURE I PLANNING 5865 Owens Drive Pleasanton. Cali fornia 94588 USA