Hazardous Area Atmosphere Zones (HAAZ)
What is a Hazardous Area Atmosphere Zone (HAAZ)?
This is an area where flammable vapour is present, or could be present as a result of the use or storage of flammable liquids at a location where containers are open, occasionally open, decanting or mixed. For example, Mixing benches, Gum/Parts wash, Mixing Room, Spraybooth, Process equipment, Chopper gun.
What type of flammable liquids constitute a HAAZ?
Hazardous Atmospheres are sometimes expressed as a percentage of vapour to proportion of oxygen – this is more defined in ASNZ60079. However, it is considered as per Regulation 10.13/17/19 Table 3 Schedule 9 – A hazardous atmosphere is triggered when the following containers are used for Class 3.1A, 3.1B, 3.1C :
100 L (if closed)
25 L (if decanting)
5 L (if open occasionally)
1 L (if in open container for continuous use)
What happens next if I have a HAAZ?
A Site is to have a formal Hazardous Area Atmosphere Zone Plan drawn up for all the Hazardous Substance Locations on a site. A HAAZ plan will, from the regulations (ASNZ60079 and ASNZ2430) determine the specific Explosive Atmospheres or Flammable Vapour Zones (0, 1 or 2) to determine the areas that are at risk of ignition.
How can ignition sources be mitigated within a HAAZ?
Risk can be mitigated by either distance, EX rated electrical fittings, Ventilation (to ASNZ4114) or an LEL Detector to warn or shutdown equipment. A HAAZ plan may be required by an Electrical Inspector to determine the correct EX rated fittings for a Hazardous Substance Location as required by the Electrical Regulations.
What do I need to do if I have an ignition source within a HAAZ?
A site if it cannot relocate or decommission an ignition source, should attain an Electrical Certificate of Compliance from a registered Electrical Inspector (or similar), certifying that the ignition points and fittings within the Hazardous Area Atmosphere Zone (Zone 1 or 2) are compliant with the Electrical regulations. Certificate is required to be re-verified every 4 years. As per ASNZ60079:14:2009 and AS/NZS 1020:1995 -
What do the regulations actually say?
10.20 Methods of complying with regulation 10.19 (1) In the case of an electrical ignition source, compliance with any one of the ex-plosion-protection techniques, or a combination of explosion-protection techni-ques, listed in section 5 of AS/NZS 60079.14:2009 relating to matters de-scribed in regulation 10.19(3)(b) are a means of meeting the requirements of regulation 10.19(3)(b).
What does WorkSafe publish about this?
Compliance Certifier Update 2018/1:- When a hazardous area is required for a class 2 or 3 substance, and the location requires a compliance certificate, under regulation 10.34(1)(d) the compliance certifier is required to verify that the hazardous area has been established in accordance with the requirements of AS/NZS 60079.10.1:2009 or a relevant safe work instrument (their is currently none), and that the hazardous area is documented (depicted on a plan).
A compliance certifier is also required under regulation 10.34(1)(i) to verify that regulation 10.26(4) is complied with. This regulation has an additional requirement that the hazardous area is maintained. The compliance certifier is expected to sight the electrical certificate of compliance (CoC), or in the case of sites established more than four years ago the electrical periodic assessment report/certificate as part of the assurance that the hazardous area is maintained.