This European Standard specifies the safety, construction and performance requirements for pressure sensing devices. This European Standard covers type testing only. It applies to pressure sensing devices for the measurement of pressures of combustible gases of the first, second and third families, air, combustion products for maximum inlet pressures up to 500 kPa (5 bar). It applies to all types of pressure sensing devices, including electronic, differential and inferential types. It specifies requirements for pressure sensing devices which are intended to be applied to steam boilers and as such need to meet increased reliability requirements. These devices are classified as PSD-S in this European Standard.