Classification, Definition & Selection of Boilers
- Details
- Category: Design, Materials, Manufacture and Installation
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APEK |
CLASSIFICATION, DEFINITION & SELECTION OF BOILERS |
APEK GN 224 Rev 1 Issued: 11/06/2014 |
Developed for: ACA, AICIP, AIES, AINDT, CAAA, Eng Aust, Met. Aust, NATA, Stds Aust, WTIA, & PE Industry & Regulators
1 Scope
This Note summarises the definitions and classification of boilers, in Figure 1 as used in Australia.
2 Purpose
To : provide up-to-date guidance to Australian pressure equipment industry;
: amend and clarify current definitions which continue to cause difficulties; and
: support the 2014 edition of AS 1228 [Ref.1].
3 Classification and Definition
These are referenced or given in Figure 1. They are based on common usage in Australia. AS 1228 [Ref. 1] and AS 4942. [Ref 2]. Numbers below in [ ] are clauses of Ref 1 which, with Ref 2, give definitions.
“Boiler” Definition Original - a vessel in which steam is generated above a pressure greater than atmosphere by the application of fire.
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Boiler (Boiler & Plant) |
Definition - now used by PE Industry see WHS Regs, AS/NZS 1200, AS 4942. (see Section)
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Fired Pressure Vessels |
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Miscellaneous Boiler [1.3.11 = Ref 2] |
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Does not include: |
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Hot Water Boiler [Ref 2] |
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Steam Boiler [Ref 2] |
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Organic Fluid Heater or Evaporator [1.3.20 = Ref 2] |
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Fired Boilers |
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Unfired Boilers |
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Unfired Pressure Vessels |
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Electric B
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Element B [1.3.9]
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Cast Iron B |
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Electrode B [1.3.8]
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Immersion EB
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External EB
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Miniature B
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Hot Water Heaters |
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Fired Heaters [Ref 2] |
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(Note 1) |
Note: 1 ASME Section 1 defines reheaters, isolated superheaters and non-integral superheaters as fired pressure vessels and require them to be built to Sect 1 or Section VIII (Pressure Vessels).
Figure 1 Main Classification of Boilers
4 Sub-Classification This is given in Figure 2 and is basedon practice in Australia, USA and Europe.
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Mobility
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Circulation
[1.3.15 = Ref 2]
[1.3.11 or Ref 4]
[1.3.17 or Ref 4] |
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P, T & Product
- Saturated steam B - Superheated steam B - Supercritical steam B - Organic fluid vapour B |
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Purpose
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Type
[1.3.19 = Ref 2] - Coil Type B (Note 2)
[1.3.10 = Ref 2] - Wet back - Dry back - Semi-wet back - Reverse fired - 1, 2 or 3 pass - Vertical B
[1.3.3 Ref 8]
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Attendance [1.3.3 Ref 3]
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Firing or Heat Source
[Solid firing may be via grate. pulverised or fluidised bed] |
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Boilers |
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Figure 2 Sub-Classification of Boilers
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[Solid firing may be via grate. pulverising or fluidised bed] |
APEK GN
5 “Boiler Plant”
.1 AS 1228 and WHS Regulations imply “boiler plant” as referenced in EN 12953 [Ref 8] and ASME Sect.1 [Ref 6].
.2 This consists of:
a) The “boiler proper” i.e. all pressure parts from the feedwater inlet (including the inlet valve) to the steam and/or hot-water outlet (including the outlet valve). This includes economisers, superheaters, reheaters, and associated connecting (integral) pipes which are heated by flue gas and are not separated from the main system by intervening shut-off devices. Also included is any piping connecting the boiler to and including the first isolating valve, including the valves and steam and water fittings. Where welded ends are used, the boiler proper begins or ends at the weld where flanges, if used, would have been fitted.
b) The following boiler “associated equipment”, when essential for the operation of the boiler plant:
- Isolated economisers, superheaters, reheaters, and associated connecting pipes;
- Expansion vessels and/or expansion tanks for plants for hot water production
- Boiler setting, thermal insulation and/or refractory and cladding;
- Installations for heat (energy) supply and heating;
- Installations for processing and feeding the fuel into the boiler e.g. mills, oil heaters etc
- Installations for the air supply and flue gas removed for the boiler e.g. fans, ducts, flue gas treatment, and chimney;
- Installations for the feedwater supply of the boiler e.g. feed pump, feedwater heater, deaerator, water treatment equipment, circulating pumps, blow down tank, cooling towers;
- All control and safety systems;
- Access facilities, structures and foundations.
.3 This distinction is made as AS 1228 and similar Standards deal primarily with design and manufacture of new boilers i.e. the “boiler proper” and refer to other Standards or contracts to cover “associated plant”.
6 New “Boiler” Definition
.1 The current definition in AS/NZS 1200, AS 4942 and Work Health and Safety Regulations are not now consistent with modern global best practice and will continue to cause some confusion particularly for the next generation.
.2 These differ.
.3 Recommended: “boiler” – a pressure vessel in which steam or other vapour is generated at a pressure above that of the atmosphere, or in which water or other liquid is heated above its atmosphere boiling temperature – all by the application of fire, the products of combustion, electrical power or similar high temperature means.
7 Basis
8 Background
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- later extended to hot water boiler where steam is not generated but water is heated to a temperature above its atmosphere boiling point. - later again extended to organic fluid instead of water e.g. Dowtherm is high allow high temperature at lower pressures than water, but require some alternative arrangements when flammable or toxic. - Also extended to other high temperature means e.g. high temperature waste gases; electricity and more recently focussed solar radiation, geothermic and nuclear. - This definition includes what is commonly called a domestic kitchen boiler for boiling food at atmospheric pressure and boiling point. - It was never intended when extending to fluids other than water that atmosphere heating of LP or low temperature gas in a pressure vessel would be called a boiler. - Hence ___ protection for the pressure vessel industry is generating steam at a pressure greater than atmospheric temperature by ___ or similar high temperature means. Some corrosion later Australia and USA external over other fluid notably ______ NZ ______ |
9 Selection of Boilers
.1 What Standard?
- Any of the boiler standards referenced above should provide boilers suitable for the types of service covered by the Standard, provided all necessary additional factors are addressed e.g. rapid pressure and temperature cycling or large number of cycles, and water treatment require special consideration.
- WHS Regulations permit any of the Standard.
.2 What type of ___ boilers? Table 1 lists the main features
APEK GN
Table 1 Comparison of Boiler Standards
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Item |
AS 1228 – 2014 |
ASME Boiler Pressure Vessels |
European Standard |
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Section I – 2010 |
Section IV (Note 1) |
EN 12952 (Note 1) |
EN 12953 – 2002 |
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Type |
All types |
“Power” Boiler |
“Heater” Boiler |
Water Tube Boiler |
Shell Boiler |
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Exclusion |
Marine Boilers |
Marine & Heater Boilers |
Marine & Power Boiler |
Shell and miniature boilers |
Water Tube, rail and marine boiler |
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Design Pressure ..Units ..Range |
P MPa > Atmospheric |
MAWP MPa > |
MAWP MPa |
PS Bar |
PS Bar >0.5 bar |
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Volume |
No Limit |
No Limit |
? |
? |
> 2 L |
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Design Temperature |
>100°C |
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> 110°C |
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Materials |
All, but only lists steels, cast irons. Others for valves and fittings. |
All |
All? |
Steel except for valves and fittings |
C, C-Mn steel except for valves and fittings |
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Design |
Includes DBA & Temperature Calculation |
Design by Formula |
Design by Formula |
Design by Formula |
Design by Formula, Temperature calculation |
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Design safety Factors Carbon Steel |
, or ( ) |
, |
, |
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, |
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Design Life |
Undefined & Specific |
Undefined only |
Undefined only |
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Undefined & Specific |
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Manufacture |
10 pages + A5 4458, 4037, 3992 |
Yes + ASME V & IX |
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Weld Production Test Plates |
Yes, but not for A1, A2, A3 Steel |
Yes but not for PN.1 materials 1 per 60 metres of weld. |
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Yes |
Yes - 1/100m of long welds Class 1 1/1000m of long welds Class 2 |
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Test Pressure |
1.5 P |
1.5 MAWP |
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Higher of: 1.25PS ; and 1.43PS (use for expanded tubes) |
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Respon…. |
Nil |
Yes 2 pages |
Yes |
Yes |
Yes 2 pages |
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Conformity Assessment |
Nil or see draft |
Yes – ASME Quality Management system NB approved inspectors (10 pages). |
Yes |
Yes = EU PED |
Yes = EU PED (12 pages) |
Notes:
- ASME IV and EN 12952 not available?
10 Recommendations
.1 AS 1228-2014 Edition include this Note suitably amended (e.g. sections 1 to 5) as new “Informative Appendix”) or refer to future PE Industry Note similar to this.
.2 Use such an appendix to cover useful information not already covered in AS 1228 but covered in both ASME and EN boiler standards to assist all concerned including purchasers, boiler inspectors, trainers and trainees.
.3 SA Committee ME-001-04 – Suggest any corrections or improvements.
11 References
1 AS 1228-2006 Pressure equipment – Boilers
2 AS 4942-2004 Pressure equipment – Glossary of terms
3 AS 2593-2004 Boilers – Safety management and supervision systems
4 AS 4942-2001 Pressure equipment – Glossary of terms
5 AMBSC Codes 1, 2, 3, 4 Miniature boilers
6 ASME Boiler Code – Section IV-2011 Heating boilers
7 ASME Boiler Code – Section I-2010 Power boilers
8 EN 12953-2002 Shell boilers
9 EN 12952- Water tube boilers