ASHRAE 62.1 / Crestline BAS Specification

ASHRAE 62.1 — Section 6.2.5

VAV box minimum airflow must never be 0 CFM in occupied mode. ASHRAE 62.1 requires minimum ventilation airflow to each zone at all times during occupancy. Setting minimum to 0 causes ventilation code violation and poor indoor air quality.

ASHRAE 62.1 — Section 6.2.7

The CO2 differential for DCV should be based on the difference between indoor and outdoor CO2 levels, not an absolute 1000 ppm indoor reading. ASHRAE 62.1 Section 6.2.7 allows DCV based on a maximum CO2 differential of approximately 700 ppm above outdoor levels (typically 400 ppm outdoor, so 1100 ppm indoor max). However, a setpoint of '1000 ppm above outdoor ambient' would be 1400 ppm — too high and not compliant. The system logic needs correction.

ASHRAE 62.1 — Ventilation

VAV boxes require an airflow measuring station (sensor ring or averaging pitot tube) to measure actual airflow for proper modulation. Without it, the controller cannot maintain setpoint.

ASHRAE 62.1 / ISO 14644-4

Clean room ductwork must NOT have internal fibrous liner. Fibers shed into the airstream and contaminate the clean space. Use smooth galvanized or stainless steel duct.

ASHRAE 62.1 Section 5.9 / OSHA 1910.94

Industrial exhaust systems require adequate makeup air to replace the exhausted volume. A closed makeup air damper creates negative building pressure, reducing exhaust hood capture velocity and potentially causing backdrafting of combustion appliances. ASHRAE 62.1 and OSHA require balanced ventilation in industrial facilities.

ASHRAE 62.2

Long flex duct runs with multiple bends severely reduce airflow. Each 90° bend in 4" flex adds ~15 equivalent feet of duct. This run has excessive pressure drop.