ASHRAE 62.1 / ISO 14644-4

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 / Crestline BAS Specification

This CO2 sensor installation meets all requirements. The 0-2000 ppm range covers the full operating range needed for DCV (outdoor ambient of ~420 ppm to maximum occupied levels around 1000-1200 ppm). The ±30 ppm accuracy meets the specification tolerance. Mounting at 4 feet (breathing zone height) on an interior wall away from supply diffusers and doors ensures the sensor reads representative room air rather than being influenced by drafts or supply air.

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.

ASHRAE 90.1 — Insulation

Chilled water pipes MUST have vapor barrier on insulation to prevent condensation. Without it, moisture penetrates insulation, causes mold, and reduces R-value to near zero.