ESFR sprinklers and mezzanines

[kurnal]

Carrying out a design review for a new warehouse where ESFR sprinklers will be installed, I assessed the design against TB209- 2004.
I noted that the areas beneath a large  mezzanine with a floor height of 6 metres had spray pattern  XHH sprinklers  specified and that no boundary conditions are specified between the two systems.

TB209 recommends ESFR under a mezzanine where the floor height exceeds 4.5 metres, and that where different systems are installed side by side that boundary conditions are applied.

When I queried it with the designers and the insurers  they were not in the least concerned and said that this part of TB209 is impracticable, and "nobody does it."

I can see the difficulty of installing ESFR inder the mezz with all the additional obstacles and steelwork to have to work around- but there must be a reason for this requirement being included?

Any advice gratefully received

[John Webb]

I don't have a copy of TB209 to hand, but is the height of 4.5m to the floor a reference to the height of the mezzanine floor above the warehouse floor? If so it may be that the use of ESFR sprinklers under such a floor is thought appropriate because at that height there is a potential capacity for large stacks of goods under the mezzanine floor in the same way that they can have large stacks elsewhere in the warehouse.
(Why did they get called ESFR, by the way? It always struck me that 'Fast Response Early Suppression' was a far more logical way of putting it!)

[kurnal]

John
Yes the floor height is as you describe. You have a good point about size of stacks- But even so there are limitations on the height of stored stacks of materials as for any installations and  whilst generally ESFR permitted stacks are higher than spray pattern stacks its normal to rely on the management to maintain some discipline ( or not!)

How about Fast Initial Response Enhanced Suppression

[John Webb]

Very neat!