Shinjo Valves-A42H Spring Loaded Safety Valve, Design Standard API 520 / API 526 / API 2000 BRIFE INTRODUCTION Safety valve is a valve which automatically, without the assistance of any energy other than that of the fluid concerned, discharges a quantity of the fluid so as to prevent a predetermined safe pressure being exceeded. A42Y-C type with carbon steel body is used for the equipment and pipeline of the air, petroleum gas, liquid etc. The working temperature is bellow 300. A42Y-P type and A42Y-R type with stainless steel (SS304, SS316) body are used for the equipment and pipeline of the quality with corrosive medium The working temperature is bellow 200â??. The valve is automatically discharge a quantity of the fluid so as to prevent a predetermined safe pressure being exceeded, and which is designed to re-close and prevent further flow of fluid after normal pressure conditions of service have been restored, it is very important over-pressure protection system in operation.