Concern has been expressed in the
electrical community regarding the aging of electrical systems
in residential occupancies, possibly resulting in fires.
A question not yet fully answered is:
"Why is there a residential electrical fire problem in
the United States, even though we have such a good code?"
Among the potential answers may be that electrical components,
like any product, age over time. Coupled with this,
residential electrical systems are seldom inspected after
original installation and original installation quality may be
a factor. This project hopes to address this issue in two
ways. First, a comprehensive survey of the condition of
representative samples of residential electrical components
installed in different eras and locations will be undertaken
to determine what characteristics may influence electrical
performance. Second, development and pilot testing of a post
fire investigation checklist will assist in documenting the
relationship between system age or installed condition and
impact on fire incidence. This project will provide critical
information to code writers—especially for NFPA 73 and the NEC® —as well as AHJs, electrical equipment manufacturers,
installers, property owners, and insurers.
Photo
1. Harvesting aged electrical components from houses
scheduled for demolition is "dirty, nasty work," but
it provides the most accurate picture of real-world
situations.
Goal
The overall goal of the project is to characterize the
condition of various age groups of residential electrical
systems, by surveying a representative sample of actual
installed systems, and to document how aging and installation
may relate to residential electrical fire experience.
Scope
The survey: A comprehensive survey
of actual installed residential electrical system components
from the service point to the outlet will be undertaken over a
period of two years. Samples will be taken from residences
constructed in this century, in age groups ranging from 1920
and earlier to 1970 and later. Their condition will be
documented and tested both on site and in a laboratory test
program. Alterations and the date of alteration also will be
documented.
The fire investigation: With the
assistance of fire and electrical inspectors, an investigation
tool or checklist will be developed which documents actual or
estimated age of components/system believed to be involved at
a residential fire’s point of origin. This tool will be
tested through use at approximately 100 fire incidences over
the project time frame.
The project has been separated into two
phases, the first being the plan development and the second
being the implementation of that plan. The project is guided
by a Technical Advisory Committee (TAC) consisting of experts
from the manufacturing, inspection and insurance industries.
It is funded by an industry consortium.
Development of
Phase I
Phase I of this project, completed in September 2004, involved
development of the electrical component sampling and analysis
procedures. The TAC determined that the most productive way to
obtain electrical components for sampling would be to harvest
them from residences that were being demolished or undergoing
renovations. This would allow access as well as removal of the
components.
The TAC developed a preliminary list of
components to be removed from the selected residences and
agreed that several "pilot programs" should be
conducted to further determine the components to be removed,
how much to remove and what would be of value during the
analysis. A total of three pilot programs were conducted in
2003 and 2004. Components were harvested and sent to
Underwriters Laboratories Inc. for analysis.
Harvesting
Procedures
Upon completion of the three pilot projects, the TAC developed
harvesting procedures for components (listed below) that could
best be analyzed and would provide the most data regarding the
effects of aging.
1. Recover 3 ft of the utility service
drop and the service-entrance cable.
2. Recover service-entrance panel and 3
ft of each branch-circuit wiring attached to the panel.
(Note: do not operate any circuit breakers).
3. Recover receptacles from kitchen,
bathrooms, laundry, outdoors, those dedicated to major
appliances, and any that may look or be suspect. Recovery
should encompass the outlet box (without disturbing any
wiring) and 3 ft of wire/pipe on each side.
4. Recover kitchen luminaires, outdoor
luminaires and any luminaires that extend into attic space.
For luminaires, also recover lamps. Recovery should include
the outlet box and 3 ft of wiring.
5. Recover some wiring system and
components from the attic and crawl space areas.
6. Recover a few junction boxes,
especially where splices may be encountered, including 3 ft
of wire from each box.
7. Devices such as meter socket, wall
switches, fans, etc., should be recovered if they show
evidence of problems.
8. Any cord sets should be recovered and
labeled as to where they were found.
Component
Analysis/Database
Each component harvested from the selected residences will be
analyzed with the test results included in a database. The
components will be subjected to testing determined by the TAC.
Testing and analysis procedures have been developed and will
include:
1. Recovered circuit breakers and fuses—calibration
and terminal tightening torque back-off measurements
2. Wire and cable—dielectric and
line-to-ground testing
3. Receptacles—temperature; and
back-off tightening torque
4. Luminaires—dielectric testing
Harvesting
Locations/Champions
The goal of the project is to obtain component samples from
approximately 100 residences located throughout the United
States. A representative sampling of locations encompassing
the majority of the environmental conditions found throughout
the country were identified. These areas are the Southeast
(Florida), Northeast (New Jersey) Southwest (Phoenix) West
Coast (California) Northwest (Oregon) and Minnesota/Wisconsin.
It was decided that in order to obtain samples from each of
these areas, volunteers or "Champions" would be
identified and asked to participate in the program. These
Champions, who typically are electrical inspectors in the
areas of interest, were contacted and all very
enthusiastically agreed to participate in the project.
Photo
2. Some of the ordinary and not so ordinary tools and
other items needed for the harvesting and recording of data
Photo
3. One of the harvesting teams takes time out to pose for
a picture. Note the absence of sterile white lab coats,
high-tech instruments, and pristine facilities one normally
envisions when they hear the words "research
project."
Phase II
Phase II of this project will implement the harvesting
procedures developed as a result of Phase I, with the goal of
harvesting and analyzing components from a minimum of 100
residences from the different geographic areas and age groups
identified, over the next two years.
Phase II will also see the development of
an enhanced fire investigation program to better understand
the relationship of electrical component aging and real fire
experience. The project will select and collaborate with an
AHJ (local government or federal agency), and with them,
develop and test a questionnaire that focuses on recording the
estimated age and installed condition of components/systems
believed to be involved at an electrical fire’s point of
origin.
The project is scheduled for completion in
2006.
Summary
The Residential Electrical System Aging Research Project,
Phase I, has achieved the following:
1. A comprehensive residence sampling
plan has been developed which defines the number, age and
location of residences determined to be representative of
conditions around the country.
2. A practical set of component
harvesting procedures has been developed and tested in three
locations.
3. A testing and analysis program has
been developed which includes both on-site and laboratory
testing designed to determine the factors that influence the
performance of aged electrical systems.
4. An implementation plan for Phase II
which includes the confirmed participation of a series of
Champions across the country is in place.
With the implementation of Phase II, the
project will develop valuable information to code writers—especially
for NFPA 73 and the NEC—and to electrical, fire and
building officials, electrical equipment manufacturers,
electrical workers, property owners, and insurers, regarding
the effects of aging on residential electrical systems as it
relates to electrical fires.
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The
Fire Protection Research Foundation
What is it?
The Foundation is a charitable organization formed
by NFPA in 1982 to address the growing need for
independent research to assist fire safety codes and
standards.
What does it do?
Three key research related activities take place at the
Foundation.
-
Determining research priorities for the fire
safety community
-
Managing collaborative research programs
-
Communicating research results at state-of-
the-art Symposia
Where and When?
The Foundation is co-located with NFPA in Quincy, MA,
and meets regularly with NFPA Technical Committees
across the country to determine the technical issues
they are facing and look for ways to assist with
research solutions.
Why the Foundation?
The Foundation has three attributes which make it an
important contributor to fire safety research:
-
An independent, highly regarded structure and
leadership
-
A direct line of communication with the re- search
needs of fire safety practitioners through the NFPA Committee
process
-
A consortium environment where interested
stakeholders can combine resources to implement research
Current Projects
-
Effect of Aging on House Wiring
-
In ground performance of electrical grounding
systems
-
FRP propane cylinders safety issues
-
Database of sprinkler test reports
-
Audibility of smoke alarms for the elderly
-
Siting distances for hydrogen fuel cells
-
Effectiveness of compartmentation in record
storage centers
-
The best way to "stop, drop and roll"
-
Passenger vehicle fire hazards review
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Kathleen H. Almand, P.E., is executive director of The Fire Protection Research Foundation. |
