The Q Advance Series Tank Mounted Air Compressors Feature an all-new, UL 508 Listed, General Air Products Digital Pressure Switch. Designed to run at an average of 58 dBA, this is a 20 dBA drop from our standard OL Series. The Q Advance Series Air Compressors are specifically designed to fill dry pipe and pre-action fire sprinkler systems to supervisory pressure within 30 minutes per NFPA 13. All tank mounted compressors require an Air Maintenance Device to regulate system pressure.