ASHRAE 15 §9.9 (Pressure-Limiting Devices)

ASHRAE 135-2016

A BACnet gateway does not satisfy a native BACnet requirement. The specification explicitly requires BACnet per ASHRAE 135-2016 and prohibits proprietary protocols. A gateway creates a single point of failure, adds latency, limits functionality (not all BACnet services translate through gateways), and locks the owner into one vendor for the field-level devices. Native BACnet means every controller communicates BACnet natively — either BACnet/IP or BACnet MS/TP — without translation. This is a critical specification requirement designed to protect the building owner from vendor lock-in.

ASHRAE 135-2016 / Crestline BAS Specification

Crestline specifications require all building automation systems to comply with ASHRAE Standard 135-2016 (BACnet). Proprietary, closed-protocol systems lock the owner into a single vendor and prevent competitive service and integration. Open-protocol BACnet is mandatory for all new installations.

ASHRAE 15

ASHRAE 15 requires a refrigerating machinery room to be separated from the rest of the building with tight-fitting, self-closing doors. The room is designed to contain a refrigerant release and exhaust it to the outdoors. Wedging the doors open defeats the containment and lets a release migrate into occupied space.

ASHRAE 170 Table 7-1

The air change rates are right but the pressure direction is backwards. ASHRAE 170 Table 7-1 requires an airborne infection isolation room to be NEGATIVE relative to adjacent spaces — exhaust must exceed supply so air flows INTO the room and is exhausted, keeping airborne pathogens from spilling into the corridor. The room protects everyone outside it from the patient. Positive pressure is what a protective environment (PE) room uses, which protects an immunocompromised patient FROM the building. The two room types have the same 12 total / 2 outdoor ACH and opposite pressure directions, which is exactly why they get mixed up. Get the direction wrong and the isolation room does the opposite of its job.

ASHRAE 170 Table 7-1 / FGI Guidelines

This passes all code requirements. ASHRAE 170 Table 7-1 specifies an OR temperature range of 68-75°F and a relative humidity range of 20-60%. The facility's 72°F and 45% RH are well within both ranges. The visible display allows the surgical team to verify conditions during procedures. The alarm capability ensures staff are notified if conditions drift out of range. The dedicated AHU with cooling, reheat, and humidification provides the three-stage control needed to simultaneously manage temperature and humidity — essential because cooling the air also removes moisture, requiring separate reheat and humidification stages.

ASHRAE 170 Table 7-1 / FGI Guidelines 2.1-3.2

This fails on multiple counts. First, ASHRAE 170 Table 7-1 requires a minimum of 12 total ACH in AII rooms — the 10 ACH provided is below the minimum. Second, AII rooms must maintain negative pressure (minimum -0.01 inches w.g.) relative to adjacent spaces, which requires the exhaust rate to exceed the supply rate — not equal it. Neutral pressure provides no directional airflow control and allows infectious aerosols to escape when doors open. Third, while HEPA filtration on the exhaust is good practice, it does not compensate for inadequate air changes or incorrect pressure relationships. The room as designed would not contain airborne pathogens.