HomeMy WebLinkAbout2018-08-28 BOS JM BOS-SC-min Joint Meeting: Selectmen and School Committee—August 28, 2018
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,Joint Board of Selectmen and School Committee Meeting
Tuesday, August 28, 2018
A3 ;Joint Meeting of the Board of Selectmen and School Committee was called to order at 6:00
p.m. on 'Tuesday, August 28, 2018 in Estabrook Hall of the Cary Memorial Building for the
Purpose reviewing the proposed emergency heating/cooling systems for the new Lexington
Children's Place (L CP). Present for the Selectmen (BC S) were Ms. Barry, Chair; Mr. Pato; Mr.
Lucente; Ms. Hai; Ms. Axtell, AssistantTown Manager; and Ms. Siebert, Recording Secretary.
Ms. Ciccolo was recused and not present.
Present for the School Committee (SC) were Ms. Jay, Chair; Ms. Colburn; Mr. Alessandrini; Ms.
Linehan; Ms. Sawhney; Dr. Hackett, Superintendent of Schools; Ms. Billings.-Fouhy, Lexington
Children's Place Director.
Also present: Mr. Cronin, Director of Facilities; Ms. DiNisco, DiNisco Design; Soon Oh, BAB
International; Chris Schaffner, Green Engineer; Kevin Murphy, Thompson Engineering (late
arrival).
Mr. Cronin said that the pending question to be determined is what the emergency power system
would be for the new 20,000 SF LLP building. An emergency generator is included in the
building plan but because the heating system would consume much of the generator's output, a
subsidiary power source is seen as necessary to extend the building's resiliency.
Ms. DiNisco cited three main points for consideration:
• What are LCP's program elements?
• Based on the program elements, what are the project parameters?
• What are the resiliency needs for the building?
"oLarns elements: LLP is Lexington's year-round, State-mandated early intervention program
for ages 2.9-5 years. Appropriate learning spaces, accessibility, and relevant services must be
provided. A medical suite and administration offices are included in the design.
The building is scheduled to be open by September 2019. 'The new LLP
building is part of the larger elementary school plan which aims, in part, to alleviate crowding at
the Harrington School. Expansion capabilities within the LLP building design allow for a higher
population.
Re,silienc �needs: The building is a hybrid of LEED design and Lexington's specific sustainable
building requirements. It will have a resiliency level of 3 or 4, the lowest of the four categories,
which is intended to preserve operations and protect the building asset. Normal operations will
use electricity-only via VRF (Variable Refrigeration Flow) using ERU (energy recovery units).
Electricity failure or VRF malfunction due to snow blockage, cold temperatures, or equipment
breakage would leave the building without the ability to function.
Joint Meeting: Selectmen and School Committee—August 28, 2018
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The design team offered the Selectmen and School Committee two options to keep internal
temperatures between 65 and 67 degrees during emergency situations, recommending Option 2
as the better choice:
Option #1 (Full capacity generator, no gas heating element) would increase the generator size
to 300kW (from 150M); increase the cost by $125,000 for generator and the direct project costs
by $200,000;
#2 (150kGenerator with a gas heating element) would maintain the generator size
at 150kW; provide a gas element to the system to be used strictly for emergency conditions; and
increase direct project costs by $6,000.
Ms. DiNisco said that a l50kW emergency generator should more than suffice, adding that
Estabrook School at 90,000 SF has a 200kW generator. The fuel options for the emergency
generator are gas or diesel but there are existing on site natural gas lines. There will be five VRF
systems to heat the building with three dedicated to the three building sections/wings. In an
emergency, while using the back-up generator, two of the three could be run at the same time
and the classroom wings could be kept at only 60 degrees and the administration module at about
32 degrees. As outdoor temperatures drop, the performance capabilities of the systems would
decrease as well.
Mr. Lucente asked how long the building should remain functional in an emergency. Dr. Hackett
said it would depend on the duration of the emergency. Natural gas would allow a longer interval
while diesel fuel would lessen the time the building could be kept operational. She believes that
Option 42 is preferable because it extends the building functionality while limiting direct cost
increases. She noted that the LLP students' ISPs contractually require theTown to provide
education, either in-house or elsewhere. LLP Director Ms. Billings.-Fouhy agreed with Dr.
Hackett's assessment and reiterated the need for Lexington to provide identified services as IEP
contracts stipulate.
Mr. Lucente asked if the generator would also power air conditioning in a hot weather
emergency and if emergency generators are used at Lexington's other school. Mr. Cronin said
the AC system would work via generator and that all the schools have back-up generators.
Mr. Pato said that the last time the LCP emergency system presentation was given, there was a
good deal of community concern about deviating from the all-electric building model. Now that
he better understands the information, he sees that in an emergency, fossil fuels would be burned
no matter what as both Option I and Option 2 use natural gas. Ms. DiNisco emphasized that gas
would only be used in emergencies; the all-electric system would be used exclusively for regular
operations.
Mr. Pato asked for clarification about generator sizing, specifically why l50kW would not be
adequate for building operations projected to require 8OkW. Mr. Schaffer said simulation model
is based on "typical use" which does not prepare for worst-case scenarios. Mr. Murphy noted
that, per electric code, the generator must be sized to provide "life safety" levels of emergency
lighting and that emergency load is approximately l30kW. Demand management protocols can
be programmed now that newer generations VRF system designs allow it.
Joint Meeting: Selectmen and School Committee—August 28, 2018
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Ms. Hai asked why costs would increase for switches if these switches are needed in baseline
designs and should be part of original cost estimates. Mr. Murphy said that if the capacity is
being doubled, transfer switches and panel boards must all be made larger, increasing costs. The
gas element, if chosen, would be built into the ventilation system; the $6,000 includes purchase
and installation of the element. Weekly testing of the system requires minimal burning of natural
gas; every six months, a one-hour test of the system would be run on 30% of the system draw.
The auxiliary heating system will be tested once a year at the start of the winter season. If the
emergency occurred in warm weather, the emergency heating element would not be triggered.
Mr. Alessandrini asked if the negative 13 degree cut off at which the VRF system ceases to
function includes a consideration of wind chill. Mr. Oh said wind chill applies to people, not
equipment.
Ms. Jay asked if the heating element would be turned on automatically or require staff
manipulation. Mr. Oh said the system is automated and programmable.
Ms. Jay asked School Committee members to choose a preferred option, resulting in unanimous
support of Option 42. Ms. Barry followed suit with the Board of Selectmen, also resulting in
unanimous support for Option 42.
Upon motion duly made and seconded, the Board of Selectmen voted 40 to adjourn at 6:39 p.m.
The School Committee followed suit with a 50 vote.
A true record; Attest:
Kim Siebert
Recording Secretary