NFPA 820 Wastewater Treatment 7.5 Ventilation Monitoring states that Supply and exhaust units "shall be fitted with flow detection devices connected to alarm signaling systems to indicate inadequate ventilation and ventilation system failure". According to Table 7.6.1 Alarm notification appliances (visual and audible alarms) shall be located at entrances to spaces and within spaces.
At our WWTP facility we have horns and strobes connected to gas detection system which provide visual and audible alarms on high and high-high gas. All ventilation equipment is equipped with flow detection devices and connected to BMS panel to provide alarm in case of equipment failure.
My question is: do we still need to provide additional horns and strobes at entrance and within spaces signaling ventilation deficiency? Or is it sufficient to have ventilation alarms on BMS panel? It might be misleading to people to have horns and strobes for gas notification and others for ventilation failure.