Sprinkler System

[Andy W]

Hi all.


We have just had a quote from a company who are going to upgrade our sprinkler system.

Currently we only have overhead sprinklers above the racking, the racking is 4 standard bays high, and two wide. We are having "in line" sprinklers installed that will be at every level, between the back to back rows. Some of the lower bays have a pick location, where small goods are stored in plastic bins, on wooden slats, there are two rows per standard bay, containing eight bins.

The guy from the sprinkler company will not sign off the system as safe unless we either; install extra sprinklers on these rows that discharge foam. Or replace the plastic bins with metal ones with holes in the bottom.

There will be quite a considerable cost to either, and my boss is less than happy.

If the sprinkler is above the two sets of plastic pick bins, and the bins have holes in them to allow the water to cascade through to the next layer- would this suffice?

I would appreciate any comments.

Thanks

Andy

[kurnal]

There are so many issues here and without detailed knowledge of the installation, the goods stored and the design criteria for the sprinklers-life safety or property protection, European or American design specification it is impossible to give other than general observations.

1- Polypropylene or polyethylene storage bins are viewed as a particular hazard because of the risk of large pools of molten plastic burning on the floor which can only be effectively extinguished by foam. But it does not sound as though you have large quantities of bins. The use of plastic bins or totes is almost universal throughout warehousing and retail sectors.

2- Any form of container may have an umbrella effect in shielding goods lower down in the racks from the sprinklers, but in addition may contain and hold sufficient water to make the racks structurally unstable. This is a much bigger factor high in the racking system and much less significant for example in the bottom row.

3- In addition to the use of plastic totes, metal and wire mesh baskets are available for picking from.

4- From the outset, consult your insurance company. They vary hugely in their interpretation and application of the standards. Some companies are extremely prescriptive and even for small-scale use of plastic tote boxes for noncombustible storage require the full implementation of the guidance, others take a much more risk-based and pragmatic view. If the upgrade of the sprinklers is purely driven by the use of plastic pick bins you will probably by shopping around find another company that is quite happy to accept the risk.

5- Ensure that your sprinkler protection company is LPCB approved.

[Andy W]

Thanks Kurnal.

They are LCPB approved.

I will speak to the insurers about it. We don't have many of the plastic bins- the reason for the upgrade is that, at the moment, we are not allowed to stack to the full height of the racking. With the in-rack sprinklers we will.

As the company burnt the last warehouse to the ground (before my time here!) you can understand their concern.

Regards

Andy

[kurnal]

If you dont have many bins the requirement for foam may be overkill, but it is what a prescriptive application of the code would suggest.

Previous versions of the code have given more flexible guidance on mixed fire risks and allowed some small pockets of higher risk but the current version does not mention this. However many insurers still take a pragmatic and more flexible view. I think it would be worth asking if you have few bins - say 5% of the bays or less.

It is more common to provide in rack sprinkers at alternate levels of the racking but I cannot comment further as I have no idea of what you are storing or any other design limitations such as water supply etc.    

[Andy W]

All sorted.

The insurance company have said that we are ok with the plastic bins, as there are not that many of them compared to the number of bays we have in the warehouse.

Thanks

Andy