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Hvac System Covid Procedures

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HVAC SYSTEM COVID PROCEDURES August 17, 2020 Prepared by: Johnson Roberts Associates 15 Properzi Way Somerville, MA 02143 Prepared for: City of Cambridge Executive Summary The HVAC COVID procedures are a compilation of Industry Standards and CDC recommendations. However, it should be noted that good PPE (personal protective equipment), social distancing, hand washing/hygiene, and surface cleaning and disinfection strategies should be performed with HVAC system measures, as studies have shown that diseases are easily transmitted via direct person to person contact, contact from inanimate objects (e.g. room furniture, door and door knob surfaces) and through hand to mucous membrane (e.g. those in nose, mouth and eyes) contact than through aerosol transmission via a building’s HVAC system. Prior to re-occupying buildings, it is recommended that existing building HVAC systems are evaluated to ensure the HVAC system is in proper working order and to determine if the existing system or its associated control operation can be modified as part of a HVAC system mitigation strategy. Any identified deficiencies should be repaired and corrected, and if the building HVAC system is a good candidate for modifications those measures should be implemented. In general HVAC system mitigation strategies should include the following recommendations: 1. Increase Outdoor Air. The OA increase must be within Unit's capacity in order to provide adequate heating or cooling so Thermal Comfort is not negatively impacted. Also use caution when increasing OA in polluted areas (e.g. High Traffic/City areas) and during times of high pollen counts. 2. Disable Demand Control Ventilation where present. 3. Utilize high efficiency MERV-13 filtration for most air handling and rooftop units. Potentially use higher Filter efficiency if the unit (fan power and associated filter rack) can accommodate. Electro- static filters may also be an option. Terminal Equipment units may not be able to accommodate higher filtration levels due to their available fan horsepower, i.e.; unit ventilators. 4. Seal edges of Filter sections with sheetmetal and foil type sheetmetal tape to avoid bypass of filters 5. Change Filters more often; particularly during time of high pollen counts. 6. Operate system in occupied mode for longer periods. 7. Consider installing separate Portable Room HEPA Filter Units. (Manufacturers include: MAFNA Heal Aire) 8. Consider installing UV (ultra-violet) emitters. Air Handling, Duct mounted or Upper Room terminal UV filters (Manufacturers include: uvresources.com; Intellipure; others) are available. For Upper Room type units installed in spaces with large ceiling heights, consider also using de-stratification fans to improve effectiveness of UV filters. 9. Consider supply side ductwork distribution cleaning. The above HVAC system modifications should be done on a building by building and zone/system by zone/system basis as not all buildings’ and building area HVAC systems are not necessarily the same as outlined in HVAC Systems Overview. Included in these procedures is building flushout period and calculated air exchanges per hour tabulations. Typical spaces have been used as the buildings were designed with the similar outside air requirements for each space/room type i.e.; classroom, office etc. The information for air changes were taken from existing drawings, balancing reports and other studies. We recommend that a Balancing Contractor verify the ventilation air flow for each type of space/room. Executive Summary The Sequence of Operations included are specific to each building as HVAC systems are not typical. Recommendations are included at the end of the Sequence of Operations. Cleaning and disinfection procedures for COVID are included at the end of HVAC Procedures for each school. Executive Summary SCHOOL INDEX CAMBRIDGEPORT SCHOOL ........................................................................................ 1 AMIGOS SCHOOL JK-8 ................................................................................................. 7 JOHN M. TOBIN ELEMENTARY SCHOOL ................................................................. 12 KENNEDY LONGFELLOW SCHOOL .......................................................................... 17 MARIA L. BALDWIN SCHOOL .................................................................................... 24 HAGGERTY SCHOOL .................................................................................................. 30 LONGFELLOW COMMUNITY SCHOOL ..................................................................... 36 FLETCHER MAYNARD ACADEMY SCHOOL ............................................................ 42 DR. MARTIN LUTHER KING, JR. SCHOOL ................................................................ 48 KING OPEN & CAMBRIDGE STREET UPPER SCHOOLS ........................................ 54 CAMBRIDGE, RIDGE & LATIN SCHOOL ................................................................... 61 WAR MEMORIAL RECREATION CENTER ................................................................. 67 MORSE SCHOOL ......................................................................................................... 73 PEABODY SCHOOL .................................................................................................... 79 GRAHAM & PARKS SCHOOL ..................................................................................... 85 CLEANING AND DISINFECTING PROCEDURES ...................................................... 91 School Index CAMBRIDGEPORT SCHOOL 89 Elm St. Cambridge, MA 02139 Page - 1 CAMBRIDGEPORT SCHOOL 89 Elm St. Cambridge, MA 02139 TABLE OF CONTENTS HVAC SYSTEM OVERVIEW ........................................................................................................................ 3 SEQUENCES OF OPERATION: .................................................................................................................. 4 AIR CHANGE CALCULATIONS: ................................................................................................................. 5 MIXED AIR CALCULATOR FOR H&V UNITS ............................................................................................ 6 Page - 2 GARCIA • GALUSKA • DESOUSA Consulting Engineers Inc. HVAC SYSTEM OVERVIEW HVAC SYSTEM OVERVIEW Date: Monday, August 3, 2020 Building Name: Cambridgeport School Location: 89 Elm Street AREA/ROOM HVAC SYSTEM TYPE FILTER REQUIRED FLUSHOUT OPERATION MERV 10 prefilter, MERV 13 bag Office VAV, heating only filter from central AHU 29.9 Days System Type 1 Gymnasium Single zone HV. heating only, wall radiators MERV 13 filter 29.9 Days System Type 1 MERV 10 prefilter, MERV 13 bag Cafeteria VAV, heating only w/ fin tube filter from central AHU 29.9 Days System Type 1 MERV 10 prefilter, MERV 13 bag Kitchen VAV, heating only w/ fintube filter from central AHU 29.9 Days System Type 1 MERV 10 prefilter, MERV 13 bag Typical Classroom VAV, heating only w/ fin tube, window AC. filter from central AHU 29.9 Days System Type 1 Page - 3 GARCIA • GALUSKA • DESOUSA Consulting Engineers Inc. SEQUENCES OF OPERATION: System Type 1 Re-circulation style air-handling unit with heating, supply fan, and separate associated return fan system 1. Unit shall operate in occupied mode 24/7 for Building Flushout. 2. Supply Fan shall start and continue to run at full design speed. HV-1 to be increased for 47,800 CFM. 3. Outside Air Damper & Re-circulation Air Damper are fixed and ventilation airflow to mix with the re- circulated room air. 4. Associated Exhaust system shall start and continue to run at a constant speed to maintain a slightly- positive space pressure. 5. Heating Section coil shall modulate to maintain discharge air temperature. 6. Unit shall run continuously to deliver constant ventilation to the spaces. 7. Unit Freeze-stat, damper failure, duct-mounted smoke detector (As-applicable), high discharge air temp, or low discharge air temp shall shutdown the unit and generate an alarm. 8. Gymnasium unit shall be balanced for 2,200 CFM outside air and 5,300 CFM return air. 9. VAV boxes shall be set at maximum design air flow (not max rated). 10. Inspect condition of existing filters. Install new filters if needed prior to flushout and change filters after to flushout. Inspect filters quarterly thereafter and replace if needed. Assure gaps are sealed around filters. 11. System shall be run in occupied mode 2 hours prior to occupancy to allow at least 2.0 air changes prior to occupancy. Hot Water Boiler Systems: 1. Provide water inhibitors and 20% glycol by volume and testing to ensure proper water treatment levels are maintained. 20% glycol will achieve 10 deg. F burst protection. 2. Check control system and control devices for proper operation. 3. Check pumps and variable-frequency drives (where installed) for proper operation. 4. For natural gas systems, check gas pressure, gas valve operation, combustion flue gas venting and combustion air systems (including combustion air fans if installed) 5. Verify proper operation of all safety devices. 6. If necessary, vent air from distribution system high points. 7. Verify expansion/compression tank pressures to ensure proper operations. 8. Verify operating temperature for 200 deg. F supply temperature. The original design requires 200 deg. F boiler water temperature. Further Recommendations: 1. Install portable HEPA filters in each space where ventilation rate is less than 2.0 or filter MERV Rating is less than MERV-13. Based upon the calculation for typical
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