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PLUMBING CONNECTION
WINTER 2015
LEGIONELLA: WHERE THE USA IS AT
FOR A 30-DAY PERIOD, THE AMERICAN SOCIETY OF HEATING, REFRIGERATING AND AIR-CONDITIONING
ENGINEERS (ASHRAE) TOOK COMMENTS ON CHANGES MADE IN THE FIFTH DRAFT OF ITS PENDING
STANDARD 188P, LEGIONELLOSIS: RISK MANAGEMENT FOR BUILDING WATER SYSTEMS, WHICH COULD
AFFECT CHANGE HERE. MATTHEW FREIJE, A WORLD LEADING LEGIONELLA EXPERT, EXPLAINS.
LEGIONELLA ABROAD
S
hould the 188P committee decide the comments
received are not substantive enough to warrant a
sixth draft, then the standard could be finalised as
early as July.
The Legionella risk reduction strategy set forth in 188P
is to implement a plan for managing building water systems
including cooling towers, evaporative condensers, whirlpool
spas, ornamental fountains, misters, atomizers, air
washers, humidifiers, and other devices that release water
droplets.
A management plan would be required for potable
plumbing systems only in buildings
that have any of the following:
(a) multiple housing units with a
centralised hot water system; (b)
more than 10 stories; (c) housing
for occupants over the age of 65;
(d) healthcare for patients staying
longer than 24 hours; or (e) an area
housing or treating persons at
especially high risk of contracting
Legionnaires’ disease.
The required components
of ASHRAE’s proposed water
management plan are essentially
identical to what the World Health
Organisation recommended in its
2007 publication Legionella and the
Prevention of Legionellosis:
∫
A list of the water management
plan teammembers:
Teams
typically consist of 10 or fewer
individuals who oversee the
program and make decisions
about it. Many others are needed to implement it.
∫
A brief description of the building water systems, with
flow diagrams:
Salient information should be included
for all of the building water systems, not just the ones
prone to Legionella growth and transmission. Simple line
diagrams should show where water is received, processed
and used. For most facilities, at least two diagrams
should be included, one for domestic (potable) water
systems and another for utility (non-potable) systems.
Flow diagrams should be simple. Cluttering them with
unnecessary details will only hinder their primary purpose.
∫
Analysis of the building water systems:
Commonly
referred to as hazard analysis, this is a brief explanation
as to why each water system does or does not present
a significant potential for Legionella growth and
transmission and, for those that do, whether it is a
location at which Legionella control measures can be
applied.
∫
Control measures:
Only what is actually done to water
systems will reduce Legionnaires’ disease, so control
measures are the most important
part of any Legionella water
management plan. The team
must come up with a specific
list of control measures for each
building water system. ASHRAE
gives a framework for the team
to fill in, stating that procedures
must be included, as applicable,
for new construction, equipment
siting, start-up and shutdown,
inspections, maintenance,
cleaning, disinfection, monitoring
(e.g., temperatures; disinfectant
levels) and water treatment. The
team must also write out steps
for responding to Legionnaires’
disease should a case occur
despite the prevention efforts.
∫
Each control measure must be
monitored to determine whether
it is performed to the standard –
called a control limit – designated
in the plan:
If the control limit is
not met, then corrective action must be implemented.
The monitoring procedure, monitoring frequency, control
limit and corrective action must be listed for each control
measure.
∫
Documentation and communication procedures:
Draft
number five of 188P instructs the team to “establish
documentation and communication procedures for all
activities of the program.”
∫
Verification procedures:
The team, or a designated