Automatic fire sprinkler system pressure relief valve. Used downstream from a pressure regulating valve to protect system components from high pressure surges. Regularly furnished: cast brass valve with ¾" / 1.9 cm NPT male inlet x ¾" / 1.9 cm NPT female outlet. Pressure setting available: 15-175 psi / 1-12 bars. Specify: adjustable or fixed where applicable.