RETA Breeze Jul-Aug 2025

MACHINERY ROOM VENTILATION: A Critical Life/Safety Issue for

Cold Storage Warehouses

M achine room emergency fan and general ventilation maintenance is sometimes overlooked or postponed in favor of more routine cold storage warehouse production facility tasks. Annual or semi-annual emergency fan maintenance is often procrastinated because ammonia leaks are rare and some cold storage plants may endure an entire lifespan without a machinery incident. However, a favorite adage from Czech novelist, Franz Kafka comes to mind: “Better to have and not need, than to need and not have.” The best way to “have when needed” is to follow guidelines outlined in ANSI/IIAR 2 American National Standard for Safe Design of Closed-Circuit Ammonia Refrigeration Systems (American National Standards Institute/International Institute of Ammo By Jeff Ledsinger and Jim Webster

nia Refrigeration) in the “Ammonia Machinery Room Ventilation” section. ANSI/IIAR 2 is invaluable for proactively ensuring emergency fan dependability through design. ANSI/IIAR 6 Standard for Inspection, Testing, and Maintenance of Closed-Circuit Ammonia Refrigeration Systems is invaluable for “have when needed” through inspection and mainte nance, however there is a lot to know about fan maintenance and upgrades that is not covered in building codes and guidelines. FAN BELT MEMORY AND BEARING ISSUES For example, belt driven fans can develop a “memory” on the fan belt, especially when the fan is used infrequently, such as the case

typically occur at either pulley position, especially since fan manufacturers aim for a 150% fan belt wrap on pulleys. Therefore, a belt parked on both pulleys for months or years at a time can deviate the belt’s natural formation and “memorize” the bend that emulates the pulley’s circumference. The belt deviation prevents smooth running that results in uneven tension, wear, and performance issues and eventually premature breakage. A belt with memory issues will also cause noise and vibration that can shorten the fan motor’s lifecycle. A similar problem arises with the infre quent use of bearings. Bearing damage can occur when the shaft rests on the same bearing surfaces for long periods. The shaft (via belt tension) and infrequent use will cause dents on the bearings and races parked in a stationery position during long periods of inactivity.

with machinery room emergency air ventilation. Memory indentation can

26 RETA.com