BS 1894:1992

Committees responsible
Foreword
Section 1. General
1.1 Scope
1.2 References
1.3 Definitions
1.4 Responsibilities
1.5 Terminology and symbols
1.6 Information and requirements to be agreed and to
      be documented
Section 2. Materials
2.1 General
2.2 Selection of materials
2.3 Material specifications
2.4 Forming of plates
Section 3. Design
3.1 Design criteria
3.2 Cylindrical shells under internal pressure
3.3 Dished and flanged ends
3.4 Welded flat ends
3.5 Bolted flat ends
3.6 Stayed flat ends
3.7 Flanges
3.8 Openings in cylindrical shells
3.9 Fillet welds attaching pads and compensating
      plates to cylindrical shells
3.10 Openings and branches
3.11 Access and inspections
Section 4. Workmanship and construction in fabrication
           other than welding
4.1 Plate identification
4.2 Cold forming of plate
4.3 Cutting of forgings
4.4 Cylindrical shells
4.5 Reinforced plates
4.6 End plates
4.7 Access and inspection openings
4.8 Seatings for mountings
Section 5. Workmanship and construction in welding
5.1 General
5.2 Materials
5.3 Design
5.4 Fabrication and welding approval
5.5 Heat treatment
5.6 Non-destructive testing
5.7 Acceptance criteria for weld defects revealed by
      visual examination and non-destructive testing
Section 6. Electrical requirements
6.1 General
6.2 Insulation
6.3 Conductors and connections
6.4 Earthing and earth terminals
6.5 Testing
6.6 Electrode boilers
6.7 Immersion element boilers
6.8 Boiler rating
6.9 Steam output
6.10 Heat output of hot water boilers
Section 7. Inspection and pressure testing
7.1 Inspectors
7.2 Inspection during construction
7.3 Pressure tests
Section 8. Documentation and marking
8.1 Drawings, documents and data sheets
8.2 Certificates
8.3 Marking
Section 9. Safety valves, fittings and mountings
9.1 Safety valves
9.2 Vent pipes
9.3 Connecting pipes for water-level fittings
9.4 Pressure gauges
9.5 Boiler feedwater valves
9.6 Boiler blowdown and drain mountings
9.7 Main stop valves for steam boilers
9.8 Temperature indicator for hot water boilers
Section 10. Automatic electric controls
10.1 Electrode boilers
10.2 Immersion element steam boilers and high voltage
      electrode steam boilers
10.3 Electric steam superheaters
10.4 High temperature switch on immersion element hot
      water boilers
10.5 Hot water boilers
Annexes
A (normative) Information to be supplied by the
      purchaser to the manufacturer
B (informative) Recommended welded connections for
      pressure vessels
C (informative) Water level indication
D (informative) Boiler operation
E (informative) Recommendations for access and
      internal inspection
F (normative) Pressure relief protective devices
Tables
1.1.1 Limits of application
2.3(1) Values of f for carbon and carbon manganese
            steels with specified minimum elevated
            temperature properties
2.3(2) Values of f for materials without specified
            elevated temperature properties
3.6.2 Thickness of plate-support constant
5.4.7(1) Number of test specimens for production
            control testing
5.4.7(2) Bend test requirements
5.5.1.1(1) Recommended preheating temperatures for
            thermal cutting of plates, sections, bars
            and forgings
5.5.1.1(2) Recommended preheating temperatures for
            welding of plates, sections, bars and
            forgings
5.6.2.2.1 Extent of radiographic or ultrasonic testing
            for butt welds
5.7 Acceptance levels
9.2 Minimum open vent pipe size
Figures
3.2.5.2 Design of saddle supports
3.3(1) Typical dished ends
3.3(2) Shape factor
3.3(3) Openings in ends
3.3(4) Limits of reinforcement
3.8.1.3 Compensation of welded branch up to one-
            third of the diameter of the boiler shell
3.8.2(1) Arrangement factor g
3.8.2(2) Branch compensation
3.9 Welding of manhole frames and compensating
            plates
4.7.3 Oval manhole frame
5.4.6.1.3 Cutting up of the test plate
5.4.7.4 Transverse bend test specimen
5.4.7.5 Side bend test specimen
5.4.7.7 V-notch test piece
5.7.2 Assessment of inclusions
B.1(1) Typical weld preparations for butt welds
            using the metal-arc process
B.1(2) Typical weld preparations for
            circumferential butt welds where the second
            side is inaccessible for welding
B.1(3) Typical weld preparations for butt welds
            using the submerged-arc welding process
B.2(1) Standard weld details
B.2(2) Transverse and longitudinal sections of
            branch connections
B.2(3) Weld details for set-in branches
B.2(4) Set-on branches
B.2(5) Set-on branch: single root run technique
B.2(6) Set-in branches: fillet weld connections
B.2(7) Set-in branches: full penetration
            connections
B.2(8) Set-in branches: full penetration
            connections welded from one side only
B.2(9) Set-on branches with added compensation
            rings
B.2(10) Set-in branches with added compensation
            rings
B.2(11) Studded connections
B.2(12) Socket welded and screwed connection
B.2(13) Flange
B.2(14) Flanges
B.2(15) Flat ends and covers
B.2(16) Attachment of bar stays
F.1 Typical pressure term relationships
List of references

Includes materials, workmanship, inspection, testing, documentation and marking of boilers utilizing electrodes or immersion elements to provide hot water, steam or superheated steam. The boilers are of cylindrical design, constructed from carbon or carbon manganese steels by fusion welding.

1.1.1 This British Standard specifies requirements for the design and manufacture, including materials, workmanship, inspection, testing, documentation and marking, of boilers utilizing electrical energy by the use of electrodes or immersion elements. The boilers dealt with are of cylindrical design, either horizontal or vertical, constructed from carbon or carbon manganese steels by fusion welding for which the limits of application are given in table 1.1.1. Table 1.1.1. Limits of application Classification Limit Class I Steam and hot water boilers which exceed the limitations specified for class II and class III boilers Class II Steam and hot water boilers the design pressure of which does not exceed 1.14 N/mm2 and the design pressure of which (in N/mm2), multiplied by the internal diameter in millimetres, does not exceed 1450 Class III Steam boilers the design pressure of which does not exceed 0.23 N/mm2 Unvented hot water boilers the design pressure of which does not exceed 0.45 N/mm2 Vented hot water boilers the design pressure of which does not exceed 0.77 N/mm2 The standard applies to electric boilers which provide hot water, steam or superheated steam for use in industrial and commercial applications. NOTE. Notwithstanding the materials quoted above this does not preclude the use of other materials, such as stainless steels or copper, copper linings, etc. (see 2.1) where the boiler otherwise falls within the limits of this specification, taking the allowable stresses from another appropriate specification. 1.1.2 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.