AS 2593-2001

1 - AS 2593-2001 BOILERS-UNATTENDED AND LIMITED ATTENDANCE
4 - PREFACE
5 - CONTENTS
7 - SECTION 1 SCOPE AND GENERAL
7 - 1.1 SCOPE
8 - 1.2 REFERENCED DOCUMENTS
8 - 1.3 DEFINITIONS
8 - 1.3.1 Acceptable, acceptance, accepted
8 - 1.3.2 Bed
8 - 1.3.3 Bed warm-up gas
8 - 1.3.4 Boiler attendant
8 - 1.3.5 Boilers
8 - 1.3.6 Chimney
8 - 1.3.7 Energy input management system
9 - 1.3.8 Flue
9 - 1.3.9 Maintenance contractor
9 - 1.3.10 Proved
9 - 1.3.11 Purging
9 - 1.3.12 Trained person
9 - 1.4 NEW DESIGNS, MATERIALS AND CONSTRUCTION METHODS
11 - SECTION 2 DESIGN AND CONSTRUCTION
11 - 2.1 GENERAL REQUIREMENTS
11 - 2.1.1 Basic design
11 - 2.1.2 Tube diameter
11 - 2.1.3 Water gauges
11 - 2.2 STEAM BOILERS (OTHER THAN ELECTRIC BOILERS)
11 - 2.2.1 General
11 - 2.2.2 Water-tube steam boilers
11 - 2.2.3 Steam boilers other than water-tube or electric boilers
12 - 2.3 HOT WATER BOILERS
12 - 2.3.1 General
12 - 2.3.2 Hot water systems
12 - 2.4 WASTE HEAT BOILERS
13 - 2.5 ELECTRIC BOILERS
13 - 2.6 SUPERHEATERS
14 - SECTION 3 BOILER MANAGEMENT SYSTEM
14 - 3.1 GENERAL
14 - 3.2 FAIL-SAFE TECHNIQUES
14 - 3.3 TEMPERATURE SUITABILITY OF COMPONENTS
14 - 3.4 COMBUSTION MANAGEMENT
14 - 3.4.1 General
15 - 3.4.2 Power-operated valves
15 - 3.4.3 Flame detectors
15 - 3.5 WATER MANAGEMENT SYSTEM
15 - 3.5.1 For steam boilers other than coil- type forced circulation boilers and electric boilers
16 - 3.5.2 Water management systems for coil- type forced circulation boilers
17 - 3.5.3 Water management systems for hot water boilers
17 - 3.5.4 Water management systems for waste heat boilers
17 - 3.5.5 Water management systems for electric boilers
19 - 3.6 ELECTRICAL POWER ISOLATION
20 - 3.7 POWER FAILURE PROTECTION
20 - 3.7.1 Design and construction
20 - 3.7.2 Hazard of overheating
20 - 3.8 CONTROL EQUIPMENT
20 - 3.9 ALARMS
20 - 3.10 VISUAL DISPLAY (FOR BOILERS EXCEEDING A POWER OUTPUT OF 500 kW)
20 - 3.10.1 General
20 - 3.10.2 Fuel-fired boilers
21 - 3.10.3 Water level security
21 - 3.11 COMBUSTION EQUIPMENT FOR FUEL-FIRED BOILERS
21 - 3.11.1 General
22 - 3.11.2 Alternative firing of main fuels
22 - 3.11.3 Alternative firing of main fuels, fluidized bed combustion boilers
22 - 3.11.4 Supplementary fuel firing
23 - 3.11.5 Combustion characteristics
23 - 3.11.6 Secure mounting
23 - 3.11.7 Adverse conditions
24 - 3.11.8 Visual flame-checking provisions
24 - 3.12 MULTIPLE-BURNER INSTALLATIONS
24 - 3.13 AIR SUPPLY AND CONTROL SYSTEM
24 - 3.13.1 General
24 - 3.13.2 Air inlets
24 - 3.13.3 Proportioning
24 - 3.14 IGNITION SYSTEM
24 - 3.14.1 Start flame or pilot ignition
24 - 3.14.2 Ignition electrodes
24 - 3.14.3 High tension components
24 - 3.14.4 Location and fixing
25 - 3.14.5 Start gas rate
25 - 3.14.6 Main burner to start at a reduced rate
25 - 3.15 MAIN FUEL FIRING RATE
25 - 3.15.1 Low-fire rate operation
26 - 3.15.2 Low-fire interlock
26 - 3.15.3 Main flame turn down and modulation
26 - 3.15.4 Main flame firing rate
27 - SECTION 4 ADDITIONAL REQUIREMENTS FOR OIL-FIRED, GAS-FIRED AND SOLID-FUEL-IN-SUSPENSION-FIRED BOILERS
27 - 4.1 APPLICATION
27 - 4.2 OPERATIONAL REQUIREMENTS FOR OIL, GAS AND SOLID-FUEL-IN-SUSPENSION MANAGEMENT SYSTEMS
27 - 4.2.1 Pre-start safety interlocks
27 - 4.2.2 Starting and operating sequence
28 - 4.2.3 Fault shutdown condition for other than forced circulation boilers
28 - 4.2.4 Fault shutdown sequence for a forced circulation boiler
29 - 4.2.5 Purging
29 - 4.2.6 Flame simulation
29 - 4.2.7 Fuel admission
30 - 4.2.8 Spark ignition period
30 - 4.2.9 Flame establishment period for spark ignition
30 - 4.2.10 Start flame proving
30 - 4.2.11 Main flame establishment period for start flame ignition
30 - 4.2.12 Ignition failure
30 - 4.2.13 Flame failure response
30 - 4.2.14 Controlled shutdown
31 - 4.3 SPECIFIC REQUIREMENTS FOR OIL-FIRED BOILERS
31 - 4.3.1 Oil fuel pretreatment
31 - 4.3.2 Gas pilot
31 - 4.3.3 Controls and safety devices
31 - 4.3.4 Fuel bypass valve
31 - 4.3.5 Steam-atomized burners
31 - 4.3.6 Fuel oil installation
31 - 4.4 SPECIFIC REQUIREMENTS FOR GAS-FIRED BOILERS
32 - 4.5 SPECIFIC REQUIREMENTS FOR SOLID-FUEL-IN-SUSPENSION-FIRED BOILERS
32 - 4.5.1 General
32 - 4.5.2 Controls and safety devices
32 - 4.5.3 Valve and piping arrangement
32 - 4.5.4 Fuel quality
33 - SECTION 5 ADDITIONAL REQUIREMENTS FOR SOLID-FUEL-FIRED (BED OR GRATE) BOILERS
33 - 5.1 APPLICATION
33 - 5.2 OPERATIONAL REQUIREMENTS FOR SOLID FUEL (BED OR GRATE) MANAGEMENT SYSTEMS
33 - 5.2.1 Pre-start interlocks
33 - 5.2.2 Start-up
33 - 5.2.3 Controlled shutdown
34 - 5.2.4 Fault shutdown
34 - 5.2.5 Purging
34 - 5.3 SPECIFIC REQUIREMENTS FOR SOLID-FUEL-FIRED (BED OR GRATE) BOILERS
34 - 5.3.1 General
34 - 5.3.2 Fuel quality
34 - 5.3.3 Combustion equipment
34 - 5.3.4 Ignition of bed fuel
34 - 5.3.5 Controls and safety devices
35 - 5.3.6 Burn-back protection
35 - 5.3.7 Power failure protection
35 - 5.3.8 Solid fuel and residue handling plant
36 - SECTION 6 INSTALLATION
36 - 6.1 STATUTORY REQUIREMENTS
36 - 6.1.1 Gas installations
36 - 6.1.2 Fuel oil installations
36 - 6.1.3 Solid fuel installations
36 - 6.1.4 Electrical installations
36 - 6.2 HOUSING, ACCESS AND SECURITY
36 - 6.3 FEEDWATER SUPPLY
36 - 6.4 WATER TREATMENT
36 - 6.5 BLOWDOWN
36 - 6.6 FLUES AND CHIMNEYS
37 - SECTION 7 MARKING AND INSTRUCTIONS
37 - 7.1 MARKING
37 - 7.2 ELECTRICAL DATA
37 - 7.3 INSTRUCTIONS
37 - 7.4 LANGUAGE AND UNITS
37 - 7.5 CERTIFICATES
38 - SECTION 8 CHECKING, TESTING AND MAINTENANCE
38 - 8.1 GENERAL
38 - 8.2 ORGANIZATION AND PERSONNEL
38 - 8.3 RESPONSIBILITIES CHECKING, TESTING AND MAINTENANCE
38 - 8.3.1 Program and procedures
38 - 8.3.2 Periodic and yearly testing and maintenance
38 - 8.4 CHECKING AND TESTING
38 - 8.4.1 Limited attendance supervision
39 - 8.4.2 Daily checking
39 - 8.4.3 Weekly checking
39 - 8.4.4 Periodic testing
40 - 8.4.5 Changes to procedures
40 - 8.4.6 Recording
40 - 8.5 MAINTENANCE
40 - 8.5.1 Periodic maintenance
41 - 8.5.2 Yearly maintenance
41 - 8.5.3 Records
41 - 8.6 RETENTION OF RECORDS
41 - 8.7 MAINTENANCE CONTRACT
41 - 8.7.1 Scope of contract
42 - APPENDIX A - LIST OF REFERENCED DOCUMENTS
43 - APPENDIX B - ACCEPTABLE CRITERIA FOR ORGANIZATIONS AND PERSONNEL UNDERTAKING BOILER CONTROL DESIGN, TESTING AND SERVICING
43 - B1 GENERAL
43 - B2 ORGANIZATIONAL COMPETENCIES
43 - B3 MINIMUM COMPETENCIES FOR PERSONNEL
43 - B3.1 General
44 - B3.2 Designer
44 - B3.3 Commissioning body
44 - B3.4 Servicing
45 - B3.5 Commissioning and servicing of electric boilers
46 - APPENDIX C - TYPE TEST FOR A BOILER SUBJECT TO POWER FAILURE
46 - C1 GENERAL
46 - C2 TYPE TEST
46 - C3 TEST PROCEDURE
46 - C4 ACCEPTANCE CRITERIA
47 - APPENDIX D - TYPICAL OIL OR GAS BURNER FIRING SEQUENCE
48 - APPENDIX E - TYPICAL OIL SUPPLY AND CONTROL SYSTEMS

Specifies requirements for boilers which are intended to be operated for periods without human supervision. The changes in this edition include the removal of all references to the regulatory authorities and the introduction of accreditation for boiler attendants, as regulatory authorities will no longer carry out certification of boiler attendants.

This Standard specifies requirements for unattended and limited attendance boilers which are intended to be operated for periods without human supervision. It includes special features within the control, management and supervision systems, associated valves and fittings, housing and installation, as well as requirements and responsibilities for checking, testing and maintenance of these boilers.The limits on the type, design criteria, and usage of unattended and limited attendance boilers to which this Standard is intended to apply are as follows: (a) Boilers for fixed land installations.(b) Boilers having a design pressure as shown in Table 1.1.(c) Boilers having a power output within the capacity specified in Table 1.1 for the boiler type and category. (See Note 1.) (d) Boilers complying with the supervision and maintenance requirements specified in Table 1.1 for the boiler type and category.(e) Boilers for the generation of steam, or other vapour, for which duty the types of boilers permitted are(i) water-tube type, electric type or small boiler types (see Table 1.1) for unattended operation; and(ii) any type of boiler for limited attendance operation (see Table 1.1).(f) Boilers for the heating of water or other liquids at a pressure above that of the atmosphere and to a temperature not less than the normal atmospheric boiling temperature of the liquid, for which duty any type of boiler complying with AS 1228 is permitted for unattended operation, provided that for other than water-tube and electric type boilers, steam or vapour is not generated in the boiler and the boiler drum or shell is fully flooded.(g) Boilers having any of the following sources of energy input:(i) Gas fuel (mains or other gases).(ii) Oil fuel with a closed flashpoint greater than 23C.(iii) Solid fuels, including solid-fuel-in-suspension.(iv) Waste heat fluids.(v) Electric power.(vi) Solar energy.NOTES:1 This Standard may also be applied to boilers outside the limits specified in Items (a) to (g) in Clause 1.1 where equivalent safety and reliability are ensured.2 Except for definitions in Clause 1.3, other clauses in the Standard refer to steam and water only. The Standard may be applied to other fluids.

First published as AS 2593-1983.
Second edition 1990.
Third edition 1995.
Fourth edition 2001.