FROM NFPA 13, 1999 EDITION 9-1.5 WATER SUPPLY TREATMENT.
In areas with water supplies known to have contributed to microbiologically
influenced corrosion (MIC) of sprinkler system piping, water supplies shall
be tested and appropriately treated prior to filling or testing of metallic
CRITERIA FROM NFPA 13, 2002 EDITION 4.3 Owners' Certificate.
The owner(s) of a building or structure where the fire sprinkler system
is going to be installed or their authorized agent shall provide the
sprinkler systems installer with the following information prior to
the layout and detailing of the fire sprinkler system:
(1) Intended use of the building including the materials within the
building and the maximum height of any storage
(2) A preliminary plan of the building or structure along with the
design concepts necessary to perform the layout and detail for the
fire sprinkler system
(3) Any special knowledge of the water supply including known environmental
conditions that might be responsible for microbiologically influenced
15.1.5* Water Supply Treatment.
Water supplies and environmental conditions shall be evaluated for
the existence of microbes and conditions that contribute to microbiologically
influenced corrosion (MIC). Where conditions are found that contribute
to MIC, the owner(s) shall notify the sprinkler system developed to
treat the system using one of the following methods:
(1) Install a water pipe that will not be affected by the MIC microbes.
(2) Treat all water that enters the system using an approved biocide.
(3) Implement an approved plan for monitoring the interior conditions
of the pipe at established time intervals and locations.
A.15.1.5 Evaluation of the water supply and environmental conditions
does not necessarily require a water sample analysis by a laboratory.
Instead, general knowledge of the long-term condition of sprinkler
systems with similar piping materials in similar environments on the
same water supply can be a sufficient evaluation.
There are several options to address the effects of MIC on sprinkler
systems. Some types of sprinkler pipe such as CPVC have not shown to
be affected by MIC. Other types of pipe are being manufactured with
a biofilm that resists the effects of MIC.
Where water supplies are treated with biocides, evaluation of the effects
of the biocide on sprinkler system components (pipe, fittings, sprinklers,
gaskets, valves, and seals) is just as important as evaluating the
effect the biocide has on the organisms. Where water treatment is selected
as the method to deal with MIC, all water entering the system during
testing or flushing needs to be treated so that the organisms don't
get a chance to establish themselves.
Since all of the conditions that can effect the growth of MIC are unknown,
a plan to sample randomly selected interior positions in the system
can be effective. The frequency and location of the interior inspections
will depend on the extent of the known MIC problem with the same water
supply and similar environmental conditions.