ACGIH Industrial Ventilation Manual Chapter 5 / OSHA 1910.94
What it means on the job
Branch duct connections entering a main collector must be properly balanced with blast gates or dampers to ensure each hood receives its design capture velocity. Unbalanced branches cause some hoods to starve while others receive excessive airflow, resulting in worker exposure to contaminants at underperforming hoods.
Tested in 1 CraftIQ puzzle
- whats-wrongIndustrial Exhaust System Errors
Related OTHER sections
ACGIH Industrial Ventilation Manual Table 5-1 / NFPA 652
ACGIH Industrial Ventilation Manual specifies minimum transport velocities of 3,500 to 4,500 FPM for metallic dust to prevent settling in ductwork. At 1,800 FPM, heavy metal particulate will accumulate in horizontal runs, reducing system effectiveness and creating a fire/explosion hazard from combustible dust buildup.
ADA 309.4 / 606.4
Faucet controls must be operable with one hand without tight grasping, pinching, or twisting of the wrist — a lever, push, touch, or sensor-operated faucet is required.
ADA 606.5 / ICC A117.1
Exposed hot-water supply and drain piping under an accessible lavatory must be insulated or otherwise configured so there are no sharp or hot surfaces — a user seated in a wheelchair cannot feel a burn on their legs.
ADC Flexible Duct Performance & Installation Standards / manufacturer instructions
Flex duct must be fully extended and supported at the manufacturer's listed spacing; a long, slack run like this adds excessive pressure drop and chokes airflow. There is no national 5-ft length cap, but flex should be kept as short and taut as practical.
AHRI 400 — Liquid to Liquid Heat Exchangers
An approach temperature of 12°F versus a 3°F design indicates severely degraded performance — the fouled plates and failing gaskets are reducing heat transfer capacity by approximately 75%. The exchanger is not meeting design conditions and is wasting energy by forcing the primary equipment to work harder.
ANSI/HI 9.6.6 Rotodynamic Pumps for Pump Piping
An elbow on the suction nozzle delivers uneven, swirling flow straight into the impeller eye, which causes cavitation, noise, vibration, and premature seal and bearing failure. ANSI/HI 9.6.6 (Rotodynamic Pumps for Pump Piping) is the standard that actually governs pump approach piping — ASME B31.9 does not address it. Standard practice is a straight run of several pipe diameters ahead of the suction, or a suction diffuser designed to straighten the flow in a short space. If a reducer is needed on the suction it should be eccentric and installed flat side up so air cannot collect in it.
CraftIQ explanations are original educational commentary written in trade language and verified against the cited standards. Always confirm requirements against the code edition adopted by your jurisdiction — this is training material, not a substitute for the code book or your AHJ.