Chapter 1 of the International Building Code and NFPA standards allows for
alternative methods and materials.
If a rational engineering analysis (including a risk assessment if need be)
convinces the AHJ (reviewing authority) to agree, then you have your
alternative design.
Alternative designs could include a:
a. linear heat detection system that initiates an old-school
oscillating monitor (this approach is highly unlikely to be effective)
b. open space separation between racks, and between racks and
solid-pile storage on the floor (note, if you are going to engage in
open space separation, convince yourself that the separation is
sufficient to work, and not just sufficient to provide a paper-based
notional fire protection scheme
c. storage/separation of goods by fire hazard class working in harmony
with method b.
d. I would separate large quantities of combustible paints (many
paints now are water-based) with berm or trench drains from remaining
commodities, and store them to less than 1.6 meters if possible.
e. take worse fire hazards and store then in a second temporary
warehouse/shed
f. erect relatively cheap (sheet metal ) compartmentation
longitudinally between racks so as to buy a handful of minutes for fire
department to set up
g. erect relatively cheap sheet metal barricades across the transverse
flues every 15 m, to slow fire growth longitudinally down the length of the
rack
h. pre-piped CAF 1.25-inch monitor nozzle mounted on back of
sacrificial pickup truck for on-site manual response (again, highly
unlikely to be effective owing to fast fire growth in racks and delayed
response).
.
If you opt out of an NFPA 13 fire sprinkler system, consider having
substantial water supply for manual response. A first, and conservative,
estimate may be found in International Fire Code, Annex B Section 105.
Of course, you could simply assume the risk of total loss. How often will
a challenging fire visit a warehouse, once every 120 - 300 building years?
Consider the possibility of arson or malicious fire start into the
equation. Consider the cost of business interruption resulting from lack
of service from the burnt building. If the building is not mission
critical, which it does not appear to be, then this may be an acceptable
option. A mission critical building would create an immediate stop to
business productivity, were the mission critical building lost.
Realize a fire in tall racks, once flames of ~ 10 cm have attached, can
grow to involve the entire height (not length) of the rack within 3
minutes. After this, the fire can create failure in the roof in less than
a handful of minutes thereafter.
*2013 NFPA 13 -1.7.1 *Nothing in this standard shall be intended to
restrict new technologies or alternate arrangements, provided the level of
safety prescribed by this standard is not lowered.
In my opinion, all the above schemes LOWER the level of safety relative to
the level of safety prescribed by 2013 NFPA 13. But if you provide
adequate exit doors, at least the LIFE SAFETY of building workers will not
significantly lowered. The life safety to fire fighters entering the
structure for fire suppression, however, would be increased without the NFPA
13 compliant system.
If your local building code, and/or local population accept larger risks
than NFPA 13 accepts, then you have the beginning of a rational analyses to
present as an alternative. One example might be a temporary warehouse
located at an oil well-head facility where existing fire protection
infrastructure (dedicated fire department or even sufficient trained
workers, water supply, water source) is non-existent. Such a remote
situation however, is exactly what the ESFR sprinkler was invented for...
an automatic, roof-only, water-based strategy to control, if not suppress,
the fire without substantial manual fire attack.
Scot Deal
Excelsior Fire/Risk Engineering
gsm: +420 722 141 478
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