1.1 This document is applicable to simple unfired steel pressure vessels, referred to as “vessel” in this document, designed for air braking equipment and auxiliary pneumatic equipment for railway rolling stock (see Clause 13). It defines three types of vessel A, B and C (see Table 1) corresponding to the current practice of European railway networks. 1.2 The vessels in this document are: a) made from a single shell; b) made from non-alloy steel; c) fabricated by welding; d) used at a maximum working pressure of 15 bar; e) the product of the maximum working pressure (in bar) and the volume (in litre): 50 bar litres < PV ≤ 10 000 bar litres; f) made of a cylindrical part of circular cross-section called the shell with two outwardly dished torispherical ends, that is two dished ends with the same axis of rotation. This document therefore does not apply to vessels with one or two flat ends or those made up of several compartments; g) calculated with a design pressure P (see 5.1.4.1.2); h) designed for a working temperature of between −40 °C and +100 °C; i) fastened to vehicles: 1) by straps for types A and B vessels, 2) by welded brackets for types B and C vessels. 1.3 In normal service, a momentary overpressure of 10 % of PS, the maximum working pressure PS, is permitted. 1.4 This document applies to the vessel proper, from the inlet connection to the outlet connection and to all other connections and fittings belonging to the vessel. 1.5 This document gives the requirements to be met for the calculation, design, fabrication, inspection during fabrication and certification of the vessel, and fittings for assembly to the vehicle. These requirements cannot be written in sufficient detail to ensure good workmanship or proper construction. Each manufacturer is therefore responsible for taking every necessary step to make sure that the quality of workmanship and construction is such as to ensure compliance with good engineering practice. This document gives: a) in Annex B, recommendations for assembly to the vehicles; b) in Annex C, recommendations for the service surveillance of type A vessels; c) in Annex D, recommendations for the service surveillance of types B and C vessels. The requirements of this document apply to vessels designed to be fitted to rail vehicles.