• If applicable

Posted Tuesday, March 2nd, 2021

Some of us know the classic case being a kid and wanting the same watch as our friend Johnny. Johnny’s parents always bought him the best and latest of everything, the latest iPhone the latest iPad the latest water-proof Garmin watch. You name it, Johnny had it or would have got it. Upon seeing this we demand the same from our parents. In a bid to stop our whining they give in and buy us a water-resistant watch. It tells time, it is black, and it is everything we want, similar to the watch Johnny has…………only there is one big difference. Johnny can go 10 meters deep in the ocean with his water-proof watch without worrying about it failing, however any more than a few consistent rainy days would ruin our water-resistant watch.

In a roundabout way, the same can be said for fire rated vs fire resistant. Let’s delve in further.

Fuelchief fire rated tank SuperVault


Fire rated, as the name suggests, means that a product has been evaluated to determine relative flame spread and smoke developed indices. Based on these indices, a rating is developed for the product. Fire-rated above ground fuel tanks typically have a variety of design features including interstitial space, double skin design, insulation, steel thickness, engineering approvals, and many more properties so when fire-tested or multi-hazard tested it either meets or surpasses testing, therefore certifying it in the field.

AS 1530.4 outlines the grading period, in minutes, for:

(a) structural adequacy;

(b) integrity; and

(c) insulation;

This grading or certification is expressed in that order, in minutes, like so: (60/60/30). This indicates it has 60 minutes of structural adequacy, 60 minutes of integrity, and 30 minutes of insulation, to withstand a fire. This could be for a building product such as cladding used in construction.

A 4-hour fire rating looks like this: (240/240/240), 240 minutes equalling 4 hours.

Fuelchief fire rated tank SuperVault
Tank that is fire resistant image


A fire-resistant rating typically means the duration for which a passive fire protection system can withstand a standard fire resistance test. This can be quantified simply as a measure of time, or it may entail a host of other criteria, involving other evidence of functionality or fitness for purpose.

A storage tank that is designed and constructed to provide fire resistant protection, is in accordance with criteria in a recognized fire code. For example, a 2-hour fire resistance test such as that to meet UL2080 specifications or SwRi 97-04 generally requires that when exposed to fire, during a period of not less than 2 hours or such an above ground tank must prevent the release of liquid (such as fuel), failure of the tank itself, failure of the tank’s supporting structure, and impairment of the venting system.

In short, it is acceptable for the fuel to catch fire as long as the tank structure stays together, the primary or inner tank does not leak, and emergency vent works to prevent explosion.

A 2 hour fire-resistant tank has the notation (120/120/ – ) – it does not have insulation so does not have a rating for the third digit (the final 120).

Depending on the use of your above ground fuel tank, whether it is to store diesel or petrol, there are factors that need to be considered so as you can make an informed decision on whether to go fire rated or fire resistant.


Key defining factors for Fire Rated Above Ground Fuel Tank

  1.  A 4-hour fire rated tank has the notation (240/240/240), most importantly it has a rating for the last class which is insulation. This tank would be fully compliant to AS1940.
  2. The contents of the tank are protected in the event of a fire, and the tank has a rating in which the contents (fuel) do not catch fire up to a certain time, in minutes
  3. The tank has an emergency vent or vents to prevent the tank from exploding in a fire occurrence.



Key Defining Features for Fire Resistant Fuel Tank

  1.  A 2-hour fire resistant tank has the notation (120/120/ – ), as it does not have insulation it does not have a rating for the third digit.
  2.  the structure and integrity of the tank is rated, however there is no rating for how the contents (fuel) will perform in a fire.
  3. The tank has an emergency vent or vents to prevent the tank from exploding in a fire occurrence.



For more information contact Fuelchief

Blog article by Praneel Lal