Home / Resources & Training / Tips of the Trade / Don't Lose Pressure Due to Undersized Couplings Don't Lose Pressure Due to Undersized Couplings Posted in Abrasive & Water Blasting, Safety Tip: #26 Use Mega Max Couplings to achieve an unrestricted air flow All hoses with an ID greater than 1 1/4" (32mm) should have Mega Max couplings fitted to reduce air flow restrictions. The advantage in using large bore hose fittings is the reduction of gasket and coupling wear. Mega Max couplings have larger coupling gaskets with larger bores. A rule of thumb is any nozzle 1/2" or above - use Mega Max couplings. In this case you would require 400 + cfm compressor for 100psi at the nozzle. An unrestricted air flow produces less pressure loss, with increased performance. Hose Selection Guide Data based of 100psi nozzle pressure uses abrasive garnet. Nozzle Number No. 4 No. 5 No. 6 No. 7 No. 8 Nozzle size 1/4" 5/8" 3/8" 7/16" 1/2" CFM @ 100psi 103 158 229 312 407 Air Hose ID (Min) 1" (25mm) 1 1/2" (38mm) 1 1/2" (38mm) 2" (50mm) 2" (50mm) Blast Hose ID (Min) 3/4" (20mm) 1" (25mm) 1 1/4" (32mm) 1 1/4" (32mm) 1 1/2" (38mm) * Keep host lengths as short as possible. If extra lengths are required, it is more efficient to run a longer air hose because the pressure loss is significantly lower in air hose. Tip: #26 Share this Download pdf Related Links > Using Triclover Couplings > Proper Installation of Blast Couplings to Blast Hoses > What Size Bull Air Supply Hose Should You Actually Use?