hundred years later, another breakthrough came along in the form of the
affordable home smoke alarm. As was the case for the sprinkler, there
was a massive fire problem to be solved. Interestingly, the breakthrough
came from a person outside the fire community. He wasn't a fire
protection equipment manufacturer, fire protection engineer, or fire
researcher. He was a small business person manufacturing electrostatic
control equipment in Lakewood, Colo. And he stumbled on the idea by
THE U.S. HAD A PROBLEM
1973, the National Commission on Fire Prevention and Control reported
that the U.S. had the highest per capita fire death rate in the
industrialized world.2 While different reporting practices
made international comparisons difficult, fire death rates were reported
as twice that of second-rated Canada, three times the U.K., four times
Japan and more than 10 times France and Italy.3
after the home smoke detector hit the marketplace in the 1970s, fire
deaths began to decline. Thirty years later, American fire deaths had
fallen 50%. The per capita death rate had dropped by nearly two
thirds-from 35 deaths per million population down to 13 (Figures 1 and
2). It's estimated that some 60,000 fire deaths did not occur that would
have if the death rate had remained constant over these three decades.
Figure 1: Civilian Fire Deaths
Source: Karter, M.J., Fire Loss in the United States During 2012, NFPA September, 2013
Figure 2: Civilian Fire Death Rate
Source: Trends and Patterns of U.S. Fire Losses in 2012, NFPA November, 2013
While the decline in fire deaths can be attributed to a number of factors (such as reductions in cigarette smoking), there can be little question the affordable home smoke alarm had a major impact. Over the same 30-year period, the number of households having smoke detectors increased from fewer than 4% to 94% (Figure 3).
Figure 3: Percent of Households with Smoke Alarms
Source: Ahrens, M., Smoke Alarms in U.S. Home Fires, NFPA September, 2011 (1977-2012), Hall, J., A Brief History of Home Smoke Alarms, NFPA May, 2000 (1970-1976 est)
story began in the 1960s when young entrepreneur Duane Pearsall was
busily at work starting up his first successful manufacturing company
called Statitrol Corporation. His product was designed to eliminate
static electricity problems. This was of particular interest to
industries such as newspaper printing, photo and data processing
operations. The operating principle was to discharge negative ions into
rooms and spaces, thereby preventing static electricity discharges. It
was simply an ion generator.
were going well and the company was starting to turn a profit. Then
disaster loomed. Customers were complaining of product failures in the
field. Something had to be done, and done fast. Nothing could have been
further from Pearsall's attention than smoke detectors.
called in his engineer/inventor consultant, Lyman Blackwell, to help
figure out why the ion generator was misbehaving. In Pearsall's words,
"Lyman kludged together" a makeshift lab experiment to measure the flow
of ions in the airstream discharging from the generator.*
* Quotes and other specific attributions to Duane Pearsall are taken from his memoir titled My Life Unfolded, published by the Pearsall family in 2009.
Not long after the
experiment was powered up, the ion concentration meter began showing
erratic readings that, at first, could not be explained. Soon, however,
Pearsall recalled that the strange readings only happened when Randy the
lab technician was in the room. Randy was a compulsive chain smoker,
sometimes lighting up at the most inappropriate times. It became clear
that the lab instruments were detecting invisible smoke particles.
Someone jokingly remarked, "We should be making smoke detectors!"
According to Pearsall's memoir, this was the " point of discovery
... the embryonic beginning of the battery-operated home smoke
With no experience in the
field, Pearsall set out to develop a smoke detection business. First to
emerge was a new hard-wired commercial system designed and patented by
Blackwell using dual ionization chambers and energy-saving inverted
triode technology, which he had also invented several years earlier.4
Introduced in 1968, the Statitrol system only required a 24 volt power
supply as opposed to the higher power requirements of other systems in
the marketplace (220 volts).
voltage, hard-wired systems were still too costly for the average
homeowner, especially for retrofitting existing homes. Pearsall forged
ahead to develop what would ultimately be a completely self-contained
battery powered home smoke alarm system about the size of a coffee cup
that could easily be attached to the ceiling with two screws. Once
again, Blackwell contributed to the technological design. His innovative
use of the Complementary Metal Oxide Semiconductor (CMOS) further
reduced electrical power requirements, helping to make the battery
energy source feasible.
Pearsall was concerned about the possibility of the batteries going dead
and disabling the detector, leaving dwelling occupants unprotected. To
guard against this, Blackwell and Statitrol's staff engineer, Paul
Staby, developed and patented self-monitoring circuitry that would cause
an audible warning when the battery strength deteriorated.5 This would end up being a key feature for overcoming resistance to the self-powered concept.
had had the "aha moment." He had a vision. He had a prototype and team
of experts at the ready. Now, using his considerable leadership skills
in the business of product development, engineering, manufacturing,
marketing, distribution and sales, he was ready to make the low cost,
self-contained battery powered smoke detection system a reality. He
would call it the " SmokeGard."*
* Due to OEM agreements and corporate purchases and sales, over the years Statitrol technology has appeared under several names
Pearsall quickly learned that a labyrinth of hurdles lay ahead in the journey toward actual retail sales. These included:
- Laboratory approval. Before retail sales could begin, the mark of approval was needed from a recognized testing laboratory. Underwriters Laboratories declined to test the product since the consensus standards of the day did not permit single station, battery-powered devices.
- Consensus Standards. NFPA Standard No. 74 Household Fire Warning Equipment did not allow the battery-powered device. Changes would have to be made.
- Fire service Opposition. Of surprise to Pearsall was opposition by many local, state, and national fire service leaders. Concerns would have to be overcome.
- Code Requirements.
Very often, sales of fire protection devices are heavily driven by
state and local code requirements and the consensus model codes upon
which they are based. None of the model codes recognized the battery
power concept. Nor did they require detection systems in dwellings.
Amendments would be needed.
With plenty of serious challenges to overcome, Pearsall set out to make the product feasible. While he was personally involved every step of the way, part of his genius was an exceptional ability to harness the involvement of other enthusiastic talents- ranging from engineers and marketing professionals to dedicated rank and file factory workers and public service advocates.
assembled an ad hoc cluster of fire community members to help him
promote understanding and resolve concerns among fire and building
professionals. This included Rexford Wilson, consulting fire protection
engineer; Denver Fire Chief Myrle Wise; and John "Gus" Degenkolb,
retired Los Angeles Fire Department officer and code consultant.
Together they talked up the idea, answered technical questions and
distributed free prototypes of the detector to movers and shakers in the
world of fire safety.
ample support from national advocates for the low-cost home smoke
detector, speedy progress was made by the Technical Committee
responsible for NFPA No. 74 Household Fire Warning Equipment.6 The standard was amended in 1972 to accommodate the self-monitoring battery power. The new language read as follows:
2030. Primary Power Supply (Monitored Battery)
2031. Household fire warning equipment may be powered by a battery provided the battery be monitored to assure that the following conditions are met:
- All power requirements are met for at least one year's life, including routine testing.
- A distinctive audible trouble signal shall be given before the battery is incapable of operating (from aging, terminal corrosion, etc.) the device(s) for alarm purposes.
- Following an alarm in which the battery(s) reaches its trouble point, the trouble signal shall operate for at least seven consecutive days.
- The audible trouble signal is produced at least every minute for seven consecutive days.
- The monitored batteries meeting these specifications shall be clearly identified on the unit or the battery compartment.
were also undertaken to modify the number of detectors required. At the
time, NFPA 74 required smoke detectors in the hallway outside bedrooms
and heat detectors "in all rooms, all closets, and in all other areas
where fires can occur." These requirements resulted in system costs that
were prohibitive for the homeowner.
Bright, a leading detection researcher at the National Bureau of
Standards (now National Institute of Standards and Technology),
estimated a cost of $700 to $1,200 to protect a typical three-bedroom
home in 1974.7 The cost factor helped define Pearsall's target..."to perfect a lifesaving product every homeowner could afford."
this time, empirical fire research was beginning to show that smoke
detectors alone provided a high rate of return in terms of lives saved
vs. system costs compared to heat detectors. The 1972 edition of NFPA 74
gave a nod to this fact by acknowledging for the first time that heat
detectors need not be mandatory in all rooms, closets, and other areas:
2412. This standard recognizes that the use of partial protection can provide some degree of life safety for sleeping occupants when a basic smoke detector is installed in the immediate area(s) of, but outside of, the bedroom(s).
few years later, Bright reported "...the 1974 edition of NFPA No. 74,
however, recognized the fact that smoke detector technology has advanced
to the point where the judicious installation of one or two smoke
detectors could be more effective than a house full of heat detectors in
alerting dwelling occupants to fire."8
THE NADER BOMB
as Pearsall was beginning to see some light at the end of the tunnel,
consumer advocate Ralph Nader threw up yet another roadblock. In 1976,
Nader filed a complaint with the Nuclear Regulatory Commission (NRC)
claiming the ionization smoke detectors produced radioactive emissions
that were hazardous to the health of people in buildings. He petitioned
the NRC to recall the detectors and ban further sales.
SmokeGard did contain a small radioactive source for the purpose of
creating ions in the detection chamber¼ as is the case for all
ionization smoke detectors. Sensitive to the health concern, Pearsall
had already changed the radioactive source from 0.5 microcuries of
Radium 226 to 1.0 microcurie of Americium 241, which was deemed to be
even more benign.
The NRC dismissed the claim, noting a person receives 100 times more background radiation due to high elevation flying round trip across the U.S. With a lot of public education effort, Pearsall was able to move forward and conquer yet another hurdle.
the first laboratory approval of the battery-powered home smoke
detector came from Factory Mutual Laboratories (now known as FM
Approvals), which had never in its 136-year history tested and approved a
household product. FM Approvals had always focused exclusively on fire
equipment for industrial and commercial applictions.
and his team would leave no stone unturned, approaching FM despite the
fact that the laboratory had no history of testing home safety products.
As it turned out, management took an interest, due in no small measure
to altristic motives of individual FM personnel. In a 1971 internal
memorandum from Approvals Manager Eugene Cray to Vice President Jack
Rhodes, Cray reported an increase in requests for fire alarm systems, in
direct proportion to public and government officials' growing concern
over the appalling loss of life resulting from home fires. Cray
recommended that FM Approvals move into the home fire alarm
weeks, a new residential approval category was authorized by management
and, with technical assistance from Rexford Wilson, tests of the
Statitrol SmokeGard Model 700 were undertaken. FM approval was achieved
in 1972. At about the same time, SmokeGard made its retail debut in the
Sears & Roebuck Spring Catalog at a list price of $37.88.
Underwriters Laboratories tested and listed the SmokeGard in 1974.
1922 - 2010
SFPE Person of the Year - 1980
With support from the likes of Wilson and Degenkolb, Pearsall first concentrated on the western U.S. region through the International Conference of Building Officials. ICBO was the first model code to incorporate requirements for smoke detectors in the hallways immediately outside bedrooms. With additional advocacy nationwide, others followed:
- 1973 - International Conference of Building Officials*, ICBO Uniform Building Code
- 1975 - Building Officials and Code Administrators*, BOCA Basic Building Code
- 1975 - Southern Building Code Congress*, SBCCI Standard Building Code
- 1975 - Council of American Building Officials, CABO One- and Two-Family Dwelling Code
- 1976 - National Fire Protection Association, NFPA 101, Life Safety Code (Tentative Interim Amendment issued in 1973)
*Later merged to form the International Code Council
state and local governments started adopting the model codes for new
construction. Some implemented self-standing home fire alarm laws and
ordinances. Ohio adopted the first state-wide requirement in 1971.9
time went on, lawmakers ventured into retroactive regulations for
existing homes, usually requiring installation of smoke detectors at the
time of a purchase and sale agreement. The easy-to-install,
battery-operated device pioneered by Pearsall made i t feasible to
retrofit the nation's vast inventory of existing residential building
stock. In 1970, virtually none of the 63 million U.S. households were
protected. Remarkably, smoke alarms would be installed in more than 90
million homes over the following three decades. (By the year 2000, the
total inventory grew to 105 million households.)10
made good progress with his smoke alarm business in a relatively short
time- at its peak Statitrol had some 1,000 employees turning out smoke
detectors. But he would be the first to tell you he didn't do it alone.
He depended heavily on Lyman Blackwell for his key role in technical
design and had help from a host of other engineers, code advisors,
public officials, and people of good will. But he brought the vision,
the passion, dogged comitment, resources, diplomacy, and entrepreneurial
skills to the cause. He was the point man who did more than anyone to
bring about this 20th Century breakthrough in life-saving technology.
David A. Lucht is a Professor & Director Emeritus, Fire Protection Engineering Department, Worchester Polytechnic Institute.
- Fitzgerald, Paul, Mawhinney, John, Slye, Orville, Water-Based Fire Suppression, History of Fire Protection Engineering, (J. Kenneth Richardson, Editor), SFPE/NFPA, 2003.
- "America Burning: The Report of the National Commission on Fire Prevention and Control", U.S. Government Printing Office, 1973.
- "International Fire Statistics, 1972," Fire Journal, NFPA, Nov. 1973.
- Blackwell, Lyman L., "Aerosol Detection Device," United States Patent 4093886A, July 6, 1976.
- Blackwell, Lyman L. & Staby, Paul A., "Self-Monitoring Battery Operated Circuit," United States Patent 3778800, April 9, 1971.
- NFPA No. 74, Household Fire Warning Equipment, NFPA, 1972 Ed.
- Bright, Richard G., Fire Journal, NFPA, Nov., 1974.
- Lucht, David A., "Legal Requirements for Fire Alarms in Ohio Dwellings," Fire Journal, NFPA, March, 1972.
- Statistical Abstract of the United States, U.S. Census Bureau, 2012.