LESSONS LEARNED
Perhaps the most
striking lesson to be learned from the One Meridian
Plaza high-rise fire is what can happen when
everything goes wrong. Major failures occurred
in nearly all fire protection systems. Each
of these failures helped produce a disaster.
The responsibility for allowing these circumstances
to transpire can be widely shared, even by those
not directly associated with the events on and
before February 23, 1991.
To prevent another disaster like One Meridian
Plaza requires learning the lessons it can provide.
The consequences of this incident are already
being felt throughout the fire protection community.
Major code changes have already been enacted
in Philadelphia (see Appendix G) and new proposals
are under consideration by the model code organizations.
These changes may eventually reduce the likelihood
of such a disaster in many communities.
1.Automatic sprinklers should be the
standard level of protection in high-rise buildings.
The property conservation and life safety record
of sprinklers is exemplary, particularly in
high-rise buildings. While other fire protection
features have demonstrated their effectiveness
over time in limiting losses to life and property,
automatic sprinklers have proven to provide
superior protection and the highest reliability.
Buildings in some of the nation’s largest
cities, designed and built around effective
compartmentation, have demonstrated varying
success at containing fires, but their effectiveness
is often comprised by inadequate design or installation
and may not be effectively maintained for the
life of the building. Even with effective compartmentation,
a significant fire may endanger occupants and
require a major commitment of fire suppression
personnel and equipment. Retrofitting of automatic
sprinklers in existing buildings has proven
effective in taking the place of other systems
that have been found to be inadequate. 2.
Requirements for the installation of automatic
sprinklers are justified bv concerns about firefighter
safetv and public protection effectiveness.
as well as traditional measures such as life
safety and property conservation.
The property protection value of sprinklers
was recognized long before life safety became
a popular justification for installing fire
protection. Life safety has become the primary
concern in recent times, justifying the installation
of automatic sprinklers in high-rise buildings.
The value of sprinklers as a means of protecting
firefighters has rarely been discussed.
Members of the fire service should promote
automatic fire sprinklers if for no other reason
than to protect themselves. Requiring the installation
and maintenance of built-in fire protection
should become a life safety issue for firefighters.8
The opposition to retrofit protection has consistently
cited cost concerns. Communities need to be
made aware that the costs they defer may be
paid by firefighters in terms of their safety.
This is above and beyond the potential loss
to citizens and businesses that is usually considered.
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3. Code assumptions about fire department
standpipe tactics moved invalid.
One of the principal code assumptions affecting fire
department operations at One Meridian Plaza concerned
the installation of standpipe pressure reducing valves.
The rationale for PRVs is the concern that firefighters
would be exposed to dangerous operating pressures
and forces
Firefighters at One Meridian Plaza had great difficulty
determining how to improve flow and pressure from
hose outlets during the fire. Even if firefighters
could have closely examined the valves, with good
light and under less stressful conditions, it is unlikely
that they would have been able to readjust the valves.
Numerical indicators on the valve stems represented
an index for adjustment not the actual discharge pressure.
(This may have confused the technicians responsible
for installing and maintaining the valves. Investigators
found valves set at “20” and “80”
on the index markings. To achieve 65 psi would have
required a setting from 88 to 91 on the index. A setting
of 150 to 158 was necessary to produce the maximum
allowable 100 psi.)
Pressure regulating devices come in three different
types:
Pressure restricting devices which reduce pressure
under flowing conditions by reducing the cross-sectional
area of the hose outlet.
Pressure control valves are pilot-operated devices
which use water pressure within the system to modulate
the position of a spring-loaded diaphragm within the
valve to reduce downstream pressure under flowing
and non-flowing conditions.
Pressure reducing valves use a spring-loaded valve
assembly to modulate the position of the valve disc
in the waterway to reduce the downstream pressure
under flowing and non-flowing conditions.
Further differentiation within each of these types
results from differences in manufacturer specifications.
(Details are provided in the Philadelphia Fire Department
fact sheet on pressure regulating devices in Appendix
G.) Some devices are field adjustable, some are not.
Some can be removed to permit full, unrestricted flow,
others cannot.
if they connected hose lines to outlets near the
base of standpipe risers of substantial height, particularly
those supplied by stationary fire pumps. For example,
in a 275 foot high standpipe zone (the highest permitted
using standard pipe and fittings), a pressure of 184
psi is required at the base of the riser to overcome
elevation and produce the minimum required outlet
pressure of 65 psi at the top of the riser. At this
pressure, a standard 2 1/2-inch fire hose fitted with
a 1 1/8-inch straight bore nozzle would produce a
back pressure (reaction force) in excess of 500 pounds.
This is a well-founded concern; however, it is built
upon the assumption that fire departments use 2 1/2-inch
attack lines and straight bore nozzles to attack fires
from standpipes. Most fire departments today use 1
3/4-inch and 2-inch hose with fog nozzles for interior
attack. These appliances require substantially greater
working pressures to achieve effective hose streams.
In the aftermath of this incident, the NFPA Technical
Committee on Standpipes has proposed a complete revision
of NFPA 149 to more closely reflect current fire department
operating practices. Section 5-7 of the proposed standard
requires a minimum residual pressure of 150 psi at
the required flow rate from the topmost 2 1/2-inch
hose outlet and 65 psi at the topmost 1 1/2-inch outlet
(presumably for occupant use). Minimum flow rates
of 500 gpm for the first standpipe and 250 gpm for
each additional standpipe remain consistent with past
editions of the standard. The proposed new requirements
limit the installation of pressure regulating devices
to situations where static pressures at hose outlets
exceed 100 psi for occupant use hose or 175 psi for
fire department use hose. This will provide substantially
greater flow and pressure margins for fire department
operations. These requirements are intended to apply
to new installations and are not retroactive.
4. The requirements and procedures for design.
installation. inspection, testing. and maintenance
of standpipes and oressure reducing valves must be
examined carefully.
The proposed revision of NFPA 14 (1993) and a new
NFPA document, NFPA 25, Standard for the Installation,
Testing, and Maintenance of Water-Based Fire Protection
Systems (1992), address many of the concerns arising
from this fire regarding installation and adjustment
of pressure reducing valves. NFPA 14 requires acceptance
tests to verify proper installation and adjustment
of these devices. NFPA 25 requires flow tests at five
year intervals to verify proper installation and adjustment.
The report of the Technical Committee on Standpipes
appears in the NFPA I992 Fall Meeting Technical Committee
Reports, pp. 331-367.
Neither of these standards proposes changes in the
performance standards for the design of pressure reducing
valves.
Standard performance criteria for the design and
operation of each type of valve should be adopted
to encourage user-friendly designs that will permit
firefighters to achieve higher pressure and flow rates
without interrupting firefighting operations. The
operation and adjustment of valves should be easy
to identify and clearly understandable by inspection
and maintenance personnel without reliance on detailed
operating or maintenance instructions.
It is extremely important to have all systems and
devices thoroughly inspected and tested at the time
of installation and retested on a regular basis. Fire
suppression companies that respond to a building should
be familiar with equipment that is installed in its
fire protection systems and confident that it will
perform properly when needed.
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