This standard specifies the requirements for the design, manufacturing, inspection and acceptance of steel horizontal vessels (hereinafter referred to as horizontal vessels). This standard is applicable to horizontal vessels with a design pressure not exceeding 35MPa and supported by two symmetrical saddle supports under uniform load. This standard does not apply to the following horizontal vessels: a) Horizontal vessels heated by direct flames and exposed to nuclear radiation; b) Horizontal vessels that are frequently transported; c) Horizontal vessels that require fatigue analysis; d) Jacketed horizontal container.