DG storage and the Acceptable Solutions

(Geoff Merryweather) #1

I was having a discussion with a fire designer today about Dangerous Goods Storage (HSNO) and what Acceptable Solution (C/AS5 or C/AS6) it would fit into for the purposes of the building consent. The building is around 500sqm, 7m high so could fit into C/AS5. The scope of the C docs is silent on the storage of flammables or special hazards other than foam plastics which are excluded from C/AS5. The HSNO certifier via NZBC F3 usually has requirements for bunding for spill containment and a 4 hour concrete bunker. I don’t know what the HSNO certifier would want above this
It is going to have “quite a lot” of Class 3.1b flammables in racks - Class 3.1b is something like isopropyl alcohol or perhaps white spirits.
Some random points -
In the Olden Days, in C/AS1, it would be WF purpose group, as would the current “classified use”. For what it is worth, the old C/AS1 allowed a heat detector alarm (3af).
There is an ENZ practice Note 18 which i suspect is out of date (2010) and doesn’t really help.

Sprinklers with rack stored flammable liquids can be a problem with expensive solutions - I remember seeing a fire test video some years ago of cooking oil(?) in racks - it was most impressive when the sprinkler spray hit it and there was fire floating across the test hall floor and a mushroom cloud above…

What is the consensus of this for the purposes of a fire report and consent to the C clauses - aside from any HSNO requirements?

  • the minimum for NZBC requirements (which realistically is what will be built)?
  • what it should be if it is not the above?

(Tania Morgun) #2

Geoff, you can’t refer to C/ASX or C/VM2, HASNO is clearly out of scope of Acceptable Solutions, or Verification Method. It is specific design, that would require some input from Worksafe certifier. If you make storage within separate fire cell, (usually block wall), it becomes “separate” building. From my experience bunding, heat detection and minor exhaust is all you require. The rest of the building can be C/ASX. Hope it helped.

(Geoff Merryweather) #3

This is a job I am helping out a friend, but I thought it is an interesting point to look at.
The HSNO compliance specialist will look after their details for the DG certification which will be included in the fire report as needed, say showing the 4 hr walls. The HSNO requirements don’t look at travel distances, alarm types, door widths and hardware etc that falls in the fire engineer’s scope in most buildings, so you have to meet both c1-c6 and F3.
This comes back to what yardstick do you use to assess C1-C6. In the example in the original post, I guess c/as5,

I find the HSNO advice and regulations difficult to follow and poorly written in many cases. Maybe I don’t deal with them enough in detail. It should be easy, with risk criteria so you can do a proper risk assessment / performance based design to suit the individual situation, but it seems very prescriptive.

(Tania Morgun) #4

Hi Geoff. Nothing wrong with using C/AS5 as a benchmark for travel distances for Type 3. “To be sure “ triple RSET, make short DEOP. Doors make min 760mm. Standard easy operable hardware. You can add panic fastenings if you prefer. By complying with D1/AS1, you deem to comply. Easy part that NASNO will have low occupancy, and we know that most likely “Design Fire “ will be ventilation limited, (fuel will be higher). Limit openings to a minimum, minimum ventilation to prevent pressure cooker situation. I would check with Fire & Emergency, any additional requests for firefighters. Peace of cake! Cheers

(Kenneth Crawford) #5

When the new HSNO regulations were put together they weren’t interested in my feedback and they made the regulations a complicated mess. As Tania has already pointed out the C Clauses have nothing to do with hazardous substances. The previous F3/AS1 before it was amended actually conflicted with the HSNO requirements at the time and the BIA should have never created F3 in the first place.

The way I view hazardous substances is that the regulations are there for the special hazards created by the substances or the containers they are stored in. Provided you satisfy NZBC Clause C, there is a HSNO design and any fire walls,etc are incorporated into the design for the building then the requirements are satisfied. Often I find that the HSNO design will call for fire walls but this leaves the business owner asking how they are supposed to achieve the FRR which is something that you can help with.

It gets a lot more interesting when you have substances that explode on contact with air, are incompatible with other substances stored nearby, or where the client needs to store 2000 kg of liquid chlorine.

(Paul Clements) #6

Hi all
The Health and Safety at Work (Hazardous Substances) Regulations 2017, as amended in 2018, is the base document for HASNO storage and use. A bit convoluted, but with a Test Certifier on board, not difficult to use. Personally, I consider every DG storage as being an alternative solution, as nothing in ASX or VM2 considers the fire growth rate that a DG store can produce. One item in your favour, is that the ignition sources are very strictly controlled, even more so now that Worksafe exists.