Loading...
HomeMy WebLinkAbout2020-06-18-PBC-min PBC Minutes 6-18-20 Members Present: ]on Himmel, Dick Perry, Chuck Favazzo, Celis Brisbin It should be mentioned that several members of the Sustainable Lexington Committee were present as was Mark Sandeen (Select Board Liaison) as well as other residents. Participating in the presentation were representatives from Tecton Architects and his Consultants as well as the Town's Sustainable Design consultant, the Green Engineer. As Co-Chair ]on Himmel opened the meeting by reading the preamble as requested by the Select Board for Remote meetings. Tecton Architects began with a PowerPoint presentation for an update on the Police Station Project. A Site Plan was shared that demonstrated some development since last meeting, showing the full Fletcher Field area, bio-retention Basin, some landscaping, an updated focus area at the front entrance to the Police station and a possible reflective space in front of the former entry that could possibly be an area for the police memorial. The overall parking count remains unchanged in this design which matches the existing parking counts' and the calculated green space area is larger than the existing condition. Generator placement and potential battery storage placement is an ongoing discussion, but are expected to go between the police station and Cary Memorial Hall. There was a reminder about the pending new antenna tower at the rear corner of the site. There was a quick walk thru of the two floor plans but little discussion as there has been no real changes since the last meeting. In general, the current design (all new construction) is approx. 5000 sf less than the prior fall 2019 plan, which was based on the preservation of two facades as previously desired' by the HDC, renovation and additions to the existing building. There was a general review of the building elevations and a perspective. The Architect commented on the color of the metal panning. The design of the overhead doors still needs work. See minutes later on for discussion on update from HDC informal hearing. 'The count includes the seven patrol cars that are to be parked within the building. The roof plan showed a solar panel layout with an attempt to show the shading impact caused by the pitched roofs. Solar panels on the roof are not part of the A/E scope of work rather the data is being provided as a reference. Given the estimates gained by the roof panels it was pointed out that the roof array might capture as much as 12.5% of the electric load on the building. Solar Canopies over the parking lot where discussed although not part of this work. It was commented that there has been much discussion about the parking canopy's and that the town should be hiring an architect to design the canopy's to be more fitting to their surroundings and not rely solely on the subsequent solar vendor. In short the solar canopies should be designed not engineered since this is an important gateway to the center of town. The Lexington/"LEED" checklist was displayed and showed 62 points as achievable and 15 as maybe. 60 Points are required for gold status, and 80 for platinum. The Architect pointed out that the project was meeting all of the Lexington checklist items. A question was asked about pilot points for Covid related issues. ]on Himmel took this opportunity to introduce Stella Carr, the Towns new Sustainability Director who was participating in the meeting. The Covid pilot points question was clarified to not infer chasing points per se, but if the Covid Pandemic brought about any thoughts on things we were already doing in the design or could easily do that might better support the Police/town in dealing with this type of event again, more of a lessons learned. The consultants and Chief will review. Continuing the Covid related discussion, there was discussion about ventilation, air changes and filtering. The highlights were that none of the air in the building is recirculated, the overall quantity of air changes in the building per hour would be reviewed. The Towns standard minimum filtering is mery 13 and that is the current plan. The air handling units are designed with pre-filtering at mery 8, which then aids the mery 13 filter. It was noted that the benefits of filtering up to Hepa or the use of ultra violet light are not fully documented as a Covid solution. During this discussion it was asked about the ventilation in the garage. The engineer pointed out that the garage was a separate ventilation system with detection equipment to monitor exhaust levels and ventilate as needed. The detention area also has its own system to comply with specific Board of Health regulations for detainee holding and the dispatch center has its own isolated system, with back up to ensure its constant operation. The rest of the facility is served by floor. Part of the discussion also involved the concept of removing the enthalpy wheel from the design and replacing it with a heat exchanger. (The enthalpy wheel allows you to extract heat from the air being discharged and adding it to the new air to help reduce energy costs.) There was a quick review of the LEED items that were indicated as Maybe's and through that discussion the Towns Sustainability Consultant felt that overall some of the consulting engineers assignment of points was conservative and some of the maybes could well turn into a yes. The design team will review further with the Town. Energy analysis calculations were discussed. Effectively the Site Energy usage and EUI index (Energy Use Intensity index) for both Air source and ground source are an improvement over the ASHRAE baseline by 30+ %.There was only slight differences between the Air and Ground source systems options in terms of site energy usage. This was surprising to some as many expected the ground source to reflect a better savings in energy. However it was pointed out that 70% of the site energy use is attributed to plug and lighting loads, so the efficiencies that might exist on ground source over air source have effect on only 30% of the energy load on the building. Additionally, the volume of equipment, computers, lighting etc. in modern buildings contributes more to the heating of the building thus the cooling load in the building is greater than the heating load and this is supported by the energy calculations. Regarding Life Cycle costing it was stated that Air source had slightly better life cycle costing but the ground source had better Green House gas rating. It was pointed out that the Green House Gas calc was immaterial as both Air and Ground source systems would be provided with green energy (not reflected in this calc) so they would both result in the same greenhouse gas rating. It was discussed that the air source and ground source systems have effectively similar maintenance costs and therefore negligible affect on the life cycle costing. There was some discussion on the approval of Air source heat pumps as the preferred HVAC option, based upon the data present to date. However it was pointed out that full value of the Town of Lexington's Life Cycle costing spreadsheet was not realized to the degree it was completed at this stage and it was agreed to meet in a sub-group sometime in the next two weeks to give Lexington the opportunity to fully apply some of the intended data to this application and have sound data to base the decision on. The architect agreed that the decision was not required tonight but needs to be made by early Design Development phase at the latest. The Architect provided a brief update of the informal HDC hearing held on June 4. Tecton reported that there was a lot of good detailed dialogue. Many HDC members didn't like the bronze color on the metal panning or the level of rustication on the brownstone base. The design of the stair tower had mixed reviews and no one seemed to like the overhead doors. There was some discussion about the front door location and why not still on the circlet and at least one person thought the design should be more modern. There was a request by at least one to eliminate the bio retention basin on the site and replace it with underground chambers, although the architect noted that was a costly alternative and would need to be considered in the evaluation. There was some discussion about generator location and screening and at the time of the informal discussion there was not a landscape site plan as part of the package so they wanted to see that. All in all, Tecton thought the overall meeting was positive with a lot of good dialogue and certainly more details to work out. It is hoped that the project would be back to the HDC in July. The project is meeting with the two liaisons again next week to debrief and discuss some of the feedback. z The Police Station front door was moved to the Massachusetts Avenue fagade to address accessibility issues. It also provides Fletcher Field folks better access to the public restrooms located in the lobby of the new Police Station. A few points raised for future Police Station project presentations: 1. Show a project schedule as first slide +- to give the viewers a sense of where we are in the timeline. 2. Always have a site plan as fully developed as possible to help give context and when showing elevations or streetscape include Fletcher field. 3. Consider recognizing any parts of the design that may support future changes in police training and community use and interaction with the Police department or facility as a result of current trends. 4. Some reference to air quality/air changes to support Indoor Air Quality. Next meeting to be scheduled after the Schematic Estimate is returned and reviewed but before going to the Select Board for SD phase approval. Meeting adjourned 8:00 PM.