NZQA unit standard 12449 version 5 Page 1 of 3
Title Demonstrate knowledge of gas combustion, burners, control systems, and flame protection
Level 4 Credits 15
Purpose People credited with this unit standard are able to: demonstrate knowledge of gas combustion and burner systems design; and demonstrate knowledge of gas burners, control systems, and flame protection systems.
Classification Gas Industry > Gas Utilisation Engineering
Available grade Achieved
Guidance Information
Definition Wobbe index is a number produced when the calorific value of a gas is divided by the square root of the relative density of that same gas.
Outcomes and performance criteria
Outcome 1
Demonstrate knowledge of gas combustion, and burner systems design.
Performance criteria
1.1 The combustion characteristics of gas are defined and related to gas burner systems design in terms of the principles of physics and chemistry.
Range Charles’ law, Boyle’s law, calorific value, gas composition, oxygen requirements, Wobbe index.
1.2 Heat transfer principles are defined and related to gas burner systems design in terms of industry usage.
Range conduction, convection, radiation.
1.3 The requirements for combustion are defined and their role explained in terms of physical laws.
Range fuel source, ignition source, oxygen.
MITO New Zealand Incorporated Ó New Zealand Qualifications Authority 2018 SSB Code 101542 NZQA unit standard 12449 version 5 Page 2 of 3
1.4 Causes of incomplete combustion are explained and the potential hazards identified in terms of industry practice.
Range lack of oxygen, chilling.
Outcome 2
Demonstrate knowledge of gas burners, control systems, and flame protection systems.
Performance criteria
2.1 Types of gas burner are described in terms of usage in domestic and industrial environments.
Range pre-aerated burners, post-aerated burners, pre-mix burners, forced draught burners, radiant burners.
2.2 Component parts of burners are described in terms of purpose and function.
Range injector, primary air port, aeration control shutter, venturi, venturi throat, throat restrictor, mixing tube, burner head, burner ports, retention ports.
2.3 Air injection systems are described in terms of natural draught and forced draught.
2.4 Faults in burner operation are described in terms of causes, and the steps to prevent them are described in accordance with company procedures.
Range unstable flame pattern, unsuitable gas flow rate, inadequate air supply, excessive air supply, linting.
2.5 Component parts of control systems for gas burners are described in terms of purpose, function, and industry usage.
Range isolation valves, control valves, governor, weep line, test cock, thermostat.
2.6 Control systems for gas burners are described in terms of pressure operated systems and electrically operated systems.
2.7 Types of flame protection system for gas burners are described in terms of purpose and industry usage.
Range bimetallic, vapour pressure, thermo-electric, flame conduction and rectification, photo-electric.
Planned review date 31 December 2019
MITO New Zealand Incorporated Ó New Zealand Qualifications Authority 2018 SSB Code 101542 NZQA unit standard 12449 version 5 Page 3 of 3
Status information and last date for assessment for superseded versions Process Version Date Last Date for Assessment Registration 1 25 September 1997 N/A Revision 2 3 August 2000 N/A Revision 3 10 October 2002 N/A Rollover and 4 20 November 2006 N/A Revision Revision and 5 17 August 2017 N/A Rollover
Consent and Moderation Requirements (CMR) reference 0014 This CMR can be accessed at http://www.nzqa.govt.nz/framework/search/index.do.
Comments on this unit standard
Please contact MITO New Zealand Incorporated [email protected] if you wish to suggest changes to the content of this unit standard.
MITO New Zealand Incorporated Ó New Zealand Qualifications Authority 2018 SSB Code 101542