Skip to Content, Skip to Navigation

Safeguard OSH Solutions - Thomson Reuters

Safeguard OSH Solutions - Thomson Reuters

Safeguard Magazine

Anhydrous ammonia danger

PADRAIC DURHAM says our slack attitude to the storage and use of anhydrous ammonia risks a serious event.

Remember the Tamahere coolstore disaster? The same blasé attitudes toward refrigeration safety that caused the death of a firefighter in April 2008 continue today. Although ammonia was not involved in the Tamahere incident it is still very close to home.

The HSNO regulations do not dictate many controls for class 2.1.1B flammable Anhydrous Ammonia (when used within refrigeration systems). No location certificates are required to ensure all safety systems are designed correctly and tested regularly, like they are with LPG for instance. Fixed gas detection generally escapes the building warrant of fitness schedule, and WorkSafe doesn’t have the engineering expertise to conduct relevant inspections.

The recent Health and Safety at Work (Major Hazard Facilities) Regulations 2016 classifies major ammonia facilities at threshold quantities of 50,000 to 200,000kg. There is only one New Zealand facility that meets this designation. As an industry, we believe all ammonia systems should be included. This is a perfect opportunity to improve standards.

If you were to take a scenario of a leaking system, the distance and area of toxic concentration does not change regardless of the volume of the system. The only variable with system volume is the duration of the release. What we call the “Bible” of ammonia refrigeration, AS/NZS 1677.2:1998 Refrigerating systems – Safety requirements for fixed applications, identifies guidance in Section 6.4.1(c) of storing self-contained breathing apparatus for use in emergencies after 950kg of refrigerant discharge. Where such controls are indicated to help isolate an uncontrolled release of a hazardous substance, it surely holds some significance regarding classification as a Major Hazard?

The same regulation defines a major incident in section 9(1)(b) as one which “exposes multiple persons to a serious risk to their health or safety (including a risk of death) arising from an immediate or imminent exposure.” If we were to release even 50g of ammonia in a room in which the authors of this regulation were gathered, I’m sure their views on threshold values would change rapidly.

Quite apart from the risk to life, in an ammonia emergency there is significant risk of financial loss from product contamination, lost production and negative press. When a release is sufficiently significant (or in some cases when the emergency services want to play it safe), bordering properties will be asked to evacuate their premises, so expect to be liable for your neighbour’s losses also.

It is frustrating to see safety serve an almost exhibitional purpose in many PCBUs – the hi-viz vests, the steel-cap boots, the signage. They are easily identified by everyone and are easily managed, and perhaps health and safety people and WorkSafe inspectors find them aesthetically pleasing. However, complex tasks like electrical circuitry, programmable logic, and the potential risks with unstable configurations are understood by few. Health and safety people need to explore outside the comfort of their office and ask questions to learn more about what is actually going on.

Too often, fixed gas detection and emergency warning systems do very little to warn anyone, if they are even installed at all. Corroded pipework is rampant everywhere, desperate for a lick of paint. Pressure relief valve outlets are commonly installed far too low down, in some cases at face height… the list goes on.

Safe management of ammonia is about compliance and maintenance. The system must be designed and installed to all of the relevant standards, and properly maintained – this is what stops the stuff falling out! As for emergency preparedness, this too is essential, but of course if the installation and maintenance is done properly an emergency is highly unlikely.

We are currently missing some key elements for success. The solution is multi-faceted but relatively simple in my view:

  • • 
    Above all, we need communication: let’s talk!
  • • 
    Insurers should ensure facilities are designed and maintained to a standard.
  • • 
    Councils sign off only once minimum standards are met.
  • • 
    IQPs to provide councils with evidence of maintenance.
  • • 
    WorkSafe to engage engineering expertise to complete regular inspections.
  • • 
    EPA to include anhydrous ammonia as a refrigerant in hazardous substance controls for location test certificates
  • • 
    EPA to create a register and monitor facilities as above.

It will take only a few decisions by a small number of people to change the current course we are on.

Padraic Durham is chair of Ammonia Safety New Zealand.

comments powered by Disqus

From Safeguard Magazine

Table of Contents