scope:

This British standard specifíes requirements for the design, construction, inspection, testing and verificalion of compliance of unfired fusion welded pressure vessels. The materials of construction are specified in section 2. The term 'pressure vessel' as used in this standard includes branches up to the point of connection to the connecting piping by bscrewing or welding, and supports, brackets or other attachments directly welded to the pressure contajning shell. The term únñred' excludes vessels that are subject to direct generated heat or llame impingement from a fíred process. It does not exclude vessels subject to electricai heating or heated process streams.

In addition to the definitive requirements this standard also requires the items detailed in 1.6 to be documented. For compliance with this standard, both the definitive requirements and the documented items have to be satisfied

This standard applies only to pressure vessels manufactured under the survey of a competent engineering inspecting Authority or Organization. The intent of this requirement is regarded as satisfied where inspection is carried out by competent pemnnel of a separate engineering inspection department maintained by the purchaser of the vessel. An inspection department maintained by the manufacturer does not satisfy this requirement except

a) that specific responsibilities may be delegated at the discretion of the Inspecting Authority or Organization; or

b) in the case of vessels for the manufacturer's own use and not for resale.

This standard applies only to vessels made by manufacturem who can satisfy the Inspecting Authority or Organization that they are competent and suitably equipped to fullil the appropriate requirements of this standard

The requirements for testjng and inspecting serially manufactured pressure vessels are given in annex V. In all other respects the appropriate requirements in the specifídon apply.

Glass lined steel vessels require special design considerations subject to the limits imposed by the method of construction which should have the agreement of the inspecting Authority.

This standard does not cover the following. a) Storage tanks designed for the storage of liquids at near atmospheric pressures, i.e. where the pressure additional to that due to the hydrostatic head does not exceed 140 mbarl) above or 6 mbar below atmospheric pressure in accordance with such standards as BS 799, BS 2594, BS 2654, BS 7777.

b) Low pressure, above ground storage tanks which have a single vertical axis of revolution designed for the storage of liquides at a pressure not exceeding 1 bar¹⁾

c) Vessels in which the stresses calculated in accordance with the equations given in section 3 are less than 10 % of the design stress permitted by section 3.

d) Strip wound compound or other special designs of vessels which may be appropriate for very high pressures.

e) 'kmsport vessels, Le. vessels used for transport of contents under pressure.

f) Vessels for specific applications which are covered by standards listed in the BSI Catalogue.

NOTE. The titles of the publications referred to in this standard are listed on the last page.

This standard does not address the nature or consequences of a fire in the vicinity of a pressure vessel. Any consideration of the effect of a fire hazard in the design of a pressure vessel would have to be under the direction of the plant owner or his responsible agent such as the plant architect'engineer, with analysis of the consequences of a fire adjacent to a pressure vessel being undertaken in accordance with a comprehensive specification of the fire conditions, impingement parametem, analytical methods and assessment criteria.

The standard addresses materials in various ways:

a) The main text gives requirements for steels.

b) Certain other materials are covered by supplements which idenhfy either where the main text is applicable or where specific requirements of the supplement apply.

¹⁾1 mbar = i@ N/m² = 100 Pa.

1 bar =10⁵ N/m² = 0.1 N / m ² = 100 kPa