Why are ammonia refrigeration systems classed as MHIs?

We take a look at Major Hazardous Installations (MHI) regulations and the legal requirements for ammonia refrigeration plants.

danger sign old warning plate with yellow and black stripes and grunge texture Any refrigeration plant that uses ammonia is considered an MHI and
therefore means it is subject to MHI regulations which is part of the
OHS Act.

By Andrew Perks

I have recently been involved in drawing up emergency plans for quite a few large ammonia plants. What surprises me is the lack of knowledge about hazards in the market place. So, I have broken into my series on the ‘Role and application of refrigeration’ to bring you something on MHI regulations to try to clear up the legal requirements for ammonia plants.

Terence Thackwary of MHR Consultants, an approved authorised inspection authority (AIA) for undertaking MHI plant inspections, replied to my query as follows…

According to the OHS Act, the definition of an MHI is as follows:

  • ‘major hazard installation’ means an installation -

(a) where more than the prescribed quantity of any substance is or may be kept, whether permanently or temporarily; or

(b) where any substance is produced, used, handled or stored in such a form and quantity that it has the potential to cause a major incident.

The above definition determines that any refrigeration plant that uses ammonia is considered an MHI and thus means it is subjected to the MHI regulations which is part of the OHS Act, explains Thackwary.

The act specifies the following responsibility in terms of who is responsible for when an MHI risk assessment needs to be done…

1. Every employer, self-employed person and user shall notify the chief inspector, provincial director and relevant local government in writing of:

  1. the erection of any installation that will be a major hazard installation, prior to commencement of erection thereof; and
  2. the conversion of any existing installation into a major hazard installation, prior to such conversion.

2. Every employer, self-employed person and user shall noti9 the chief inspector, the local government and the provincial director within 60 days of the promulgation of these regulations of an existing major hazard installation.

3. No employer, self-employed person and user shall modify an installation by increasing its storage, production capacity, altering the process or by effecting any other change that may increase the risk of an existing major hazard installation, without notifying the chief inspector, relevant local government and provincial director in writing.

It is imperative that the local authority be notified about a MHI installation that has been installed or has been upgraded.

The local authority has the following duties as per the act:

1. Without derogating from the provisions of the National Building Regulations and Building Standards Act 1977 (Act No. 103 of 1977), no local government shall permit the erection of a new major hazard installation at a separation distance less than that which poses a risk to:

  1. airports;
  2. neighbouring independent major hazard installations;
  3. housing and other centres of population; or
  4. any other similar facility.

Provided that the local government shall permit new property development only where there is a separation distance which will not pose a risk in terms of the risk assessment.

The local government shall prevent any development adjacent to an installation that will result in that installation being declared a major hazard installation.

2. Where a local government does not have facilities available to control a major incident or to comply with the requirements of this regulation, that local government shall make prior arrangements with a neighbouring local government, relevant provincial government or the employer, self-employed person and user for assistance.

3. All off-site emergency plans to be followed outside the premises of the installation or part of the installation classified as a major hazard installation shall be the responsibility of the local government.

As can be seen from the above, should you not notify the local authority with regards to an MHI, the owner of the property can be held liable for the damage caused as it is a legal requirement to notify the local authority. The responsibility of offsite emergency is transferred from the property owner to the local authority in the event of an emergency.

A site that has been registered as a MHI also has the legal right to determine what developments are done in close proximity to the site. A case in point is the Burgundy Estate development next to the crude oil facility in Richwood. SFF has made it clear that there is a clearance zone around the depot and the City of Cape Town and Burgundy development has been trying for years to get this exclusion zone lifted but without the blessing of SFF it is not going to happen, explains Thackwary.

All that said, it should be appreciated that the MHI regulations currently are under review and it is expected that all facilities that have hazardous material will be classed as MHIs. The question will be to what level? The proposal is that there will be three levels as follows:

  • Level 1: A plant that is in legal conformity with regulations ie. SANS 10147.
  • Level 2: A plant that is in the process of coming inconformity with legal requirements.
  • Level 3: A plant that is a major risk.

The biggest risk will always be the human factor – the plant operators. Site training such as Ammonia Site Incident Response is a good way to ensure that any site is prepared and ready for an incident. It really is the only way to ensure that things don’t get out of control as they can very quickly if you are not prepared.



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