instead of glass.
Pierce. Octavius Pierce of Chicago
patented a sprinkler in 1894 which was
assigned to the Underwriters' Fire Sprink-
ler Co. It was a valve sprinkler with a
strut built upon somewhat the same prin-
(Section') ciple as the Newton head. It was used
to some extent in the West.
Rockwood. Geo. I. Rockwood of Worcester patented
a sprinkler head in 1906 which was modified and approved
in 1907. This was a valve sprinkler with a silver washer
under the brass valve cap. The valve was held in place
by a four-piece strut in the form of a triangle with the
LATER DEVELOPMENTS, ETC. 61
vertical member a little off center. The deflector was a
" double decker," part being under and part over the
main casting. This head was slightly modified during
the next two years, the new designs being known as
issue B, C and D. In the issue C head the solder
joint was strengthened. In the issue D type the double
deflector was abandoned and a single deflector on the
outside of the frame was substituted.
This head was originally installed by the Worcester
Fire Extinguisher Co., the company being later reor-
ganized as the Rockwood Sprinkler Co. The head is
being extensively used today all over the country. The
issue A type gave some trouble by opening prema-
turely, on account of the weakness of the solder joint.
These were practically all replaced by the makers. The
other types are entirely satisfactory.
Walworth. This sprinkler was very extensively used,
especially in New England, from the time it was in-
vented, 1883, down to 1901. There are nine distinct
types recognized besides a few minor modifications
which are not important.
In all these types the same general characteristics
were retained. Up to 1888 it was distinctly a pendent
head and would not operate properly in any other posi-
tion. In that year the first upright heads were made,
a spring being inserted to throw up the deflector and
hold it in that position. In 1892 a specially designed
upright head, known as No. 5, was made in which the
valve was held closed by a lever with an upright arm.
The deflector, which was perfectly smooth, was attached
to the upper part of the frame.
In 1894 this head was improved by making the deflec-
tor cup shaped, with perforations near the edge and by
putting on a double link to lessen the danger of prema-
In 1898 the pendent head was improved and a new
AUTOMATIC SPRINKLER PROTECTION
head, known as No. 8, with a greatly improved deflector
was substituted. The next year the upright head was
improved in a similar manner. All the later types had
double links and it was customary to wire these two
links together. Occasionally these were wired on the
side (long dimension) instead of on the end, thus bind-
ing the sliding parts together and preventing the proper
operation of the head.
The Walworth head was generally approved by local
boards and the Factory Mutual Insurance Companies
and was extensively used until 1901 when the Walworth
Manufacturing Co. sold the sprinkler business to the
Manufacturers Automatic Sprinkler Co. and the head
was no longer made. This head had a good record up
to about 1911 when tests showed that its age limit had
been about reached, as many heads that were tested
about that time either stuck or
were very sluggish in action. It
did not resist corrosion as well
as many types and in many in-
stances there were defects in work-
manship. Numerous cases have
been discovered where high-test
solder was carelessly used on low-
test heads. It is today considered
defective and is being very gen-
Esty. This head was patented
by William Esty of Laconia,
N. H., in 1895. It was a valve
sprinkler with a solder joint of
The first four types, known as the
and "pin," were ex-
the duck-bill type.
"plain," "corrugated," "knob,
perimental types and but few of them were installed.
In 1896 the No. 5, or spring type, was invented in
which the duck bills were soldered together for part of
LATER DEVELOPMENTS, ETC. 63
their length, the rest of the surface being cut out to
form a pocket in which a steel spring was inserted.
This pocket was filled with wax to protect the spring
In 1903 the head was slightly modified and the new
type was known as No. 6.
This head was never approved by the Underwriters
Laboratories. The issue B sprinkler made in 1912
was approved and this type has been extensively in-
stalled since then.
They are made by the Esty Sprinkler Co. of Laconia,
N. H., and are installed mostly by the
H. G. Vogel Co. of New York and
Babcock. The Babcock sprinkler was
patented by E. F. Steck of Chicago in
1897. It was installed by the Fire ^
Extinguisher Manufacturing Co. of
Chicago. A few thousand were installed.
After a few years these heads gave
trouble on test by sticking of the strut BABCOCK.
levers and sticking at the seat and most
of them were removed. The head was of modern design,
the valve disc being hollow, and held in place by a strut.
Grinnell. The General Fire Extinguisher Co. is per-
haps the best-known sprinkler company in the country,
and in fact in the world. There have been more Grin-
nell sprinklers than any other make installed in this
country and they are very extensively used abroad.
Starting with the Providence Steam & Gas Pipe Co. a
small piping concern in Providence, R. I. Mr. Frederick
Grinnell, by his ingenuity as an inventor and ability as
an organizer, soon made the company famous through-
out the world.
In 1893 the company was reorganized as the General
Fire Extinguisher Co. with offices and factory at Provi-
64 AUTOMATIC SPRINKLER PROTECTION
dence, R. I., and plants at Warren, 0., and Charlotte,
N. C., Mather & Platt, Ltd., were appointed agents for
Great Britain and. the continent with a factory at
The General Fire Extinguisher Co. was the first com-
pany to put on the market a full line of automatic
sprinkler system devices including, besides the sprinkler
head, a dry-pipe valve and an alarm valve.
GRINNELL GLASS Disc.
The four types of Grinnell metal disc sprinklers were
made from 1882 to '88, and were all similar in construc-
tion. The principal differences were in the kind of
metal used for the valve disc and the width and shape of
the seat ring. In 1890 the Grinnell glass disc sprinkler,
which is essentially the same as the head now used, was
invented. This was quite different from the metal disc
heads in appearance but embodied many of the same
LATER DEVELOPMENTS, ETC. 65
principles. The same style of diaphragm was used but
the valve cap, instead of being of metal and seating on
a raised rim formed in the diaphragm, was of glass and
projected into the J-inch hole in the diaphragm. The
GRINNELL SPRINKLERS IN A DEPARTMENT STORE. PIPING CON-
CEALED AND CEILING DECORATED BY ROSETTES OF A SIMILAR
SHAPE TO A SPRINKLER. ROSETTES OMITTED AT PROPER PLACES
AND SPRINKLERS SUBSTITUTED.
diaphragm was made thicker so that it needed no aux-
iliary plate to prevent collapse when the pressure was
released. The glass disc was semi-spherical in shape,
the curved side resting in the orifice and the flat side
being protected by a metal cap. The orifice was faced
with hard solder so that a tight joint could readily be
66 AUTOMATIC SPRINKLER PROTECTION
The valve was held in place by a strut composed of
three interlocking pieces of metal soldered together.
The deflector was quite small in diameter and had a
row of teeth projecting from the circumference at almost
a right angle. The head was improved in 1903 by mak-
ing the frame heavier and the deflector thicker but no
change was made in the principles involved.
The head is especially neat and symmetrical in ap-
pearance and is particularly well adapted for decora-
tive effects with concealed piping. It has now been on
the market for twenty-three years practically in its
present form and has very seldom failed to operate
from the effect of age alone.
The General Fire Extinguisher Co. has absorbed many
of its competitors, including the Neracher, Hill, Granger,
Gray, Star, Jahn, Swan and Harkness companies.
While the approved sprinklers of today may not be
perfect it is certain that they have been developed to a
point where there is little in the way of improvements
that can be suggested. The test of time may show
defects that cannot now be predicted but, taken as a
whole, the automatic sprinkler is an extremely reliable
TESTS AND CHARACTERISTICS OF
The first important tests upon automatic sprinklers
made by the insurance interests were those of the Factory
Mutual Fire Ins. Cos. in 1884. These tests were made
by Mr. C. J. H. Woodbury, Inspector, and afterwards
Vice-President of the Boston Mfg. Mutual Ins. Co.,
assisted by Mr. F. E. Cabot, Inspector and afterwards
Secretary of the Boston Board of Fire Underwriters.
These tests were extremely comprehensive and were
reported in a pamphlet covering 58 pages. The follow-
ing heads were tested: Parmelee 5, Grinnell "B," Brown
standard (sealed type), Brown sensitive, Walworth
soldered arm, Walworth solder link, Burritt sealed (rose
type), Burritt sensitive 3, Bishop sealed 1, Bishop sealed
1J, Bishop sealed 2, Bishop valve deflector with cup joint,
Bishop valve deflector with conical sleeve, William Kane
Eclipse 2, Harris deflector, Harris closed, Whiting
Hub, O. C. Heath (revolving head), Ruthenburg.
The results and conclusions are summarized as follows :
" 1st. That time and pressure has not affected the strength and
fusion point of the solder during an experience of twelve years.
2nd. Portions of sprinklers where corrosion might interfere
with prompt action should be protected, preferably by heavy
3rd. The distribution of water between three and thirty-six
pounds pressure is such that water is directed upon a smooth ceiling
and upon each square foot of floor, with all of the sprinklers used
in these experiments.
68 AUTOMATIC SPRINKLER PROTECTION
4th. The concentration of water at the beginning of a fire is
greater than by any other form of inside apparatus.
5th. Where tanks are used for a first supply for sprinklers, the
bottom of the tank ought not to be less than ten feet above the
Qth. As a matter of practical application, sprinklers have worked
at 131 mill fires in seven years without any known instance of their
7th. The results of the experience in respect to automatic sprink-
lers demonstrate that their efficiency is not liable to become impaired
by time, and prove the good judgment of those underwriters who
advocate their introduction as a safeguard against loss.
8th. It is essential that valves be so arranged that the proper
persons can readily know that a full-water pressure is upon the
sprinklers. Valves with traveling stems are preferable on this
account. Valves with stationary stems can be fitted to show their
position by winding around the valve stem a line with a weighted
tag at the end. When the valve is open or shut, the tag will hang
in a corresponding extreme position of the line. Left-hand valves
should not be used in sprinklers. It is well to secure the valves
open with a riveted strap; if it is necessary to shut the valve on
account of mishap, anybody can cut it; but do not use a lock and
chain, as the key will, in the- nature of things, be lost, and the valve
spindle bent, in the efforts to sunder the chain."
Sensitiveness. Tests on sensitiveness were made as
"With the purpose of employing a method which would give
precise results, the following apparatus was devised for the object
of learning the relative sensitiveness of automatic sprinklers under
pressure: A box of thirty cubic feet capacity, measuring three by
four feet, and two and a half feet deep, was swung top downwards
over a large table. A Par melee sprinkler head projected through
the center of the table, and was connected with a piece of four-inch
pipe about two feet long, which was beneath the table, and capped
at both ends. Water was placed in the lower end, and connections
were made with a steam supply and a steam gauge. This arrange-
ment served to furnish a supply of saturated steam at any desired
pressure, and therefore the quantity of heat and its temperature
could be known and controlled. The sprinklers were screwed into
a framework of fittings which was placed on the table, so that the
sprinklers under trial were about two feet above the table. The
TESTS AND CHARACTERISTICS OF SPRINKLERS 69
sprinklers were filled with water at the temperature of the room,
and weights applied in such a manner as to be equivalent to a water
pressure of fifteen pounds to the square inch upon the sprinklers.
Electric apparatus was attached, so that when any sprinkler opened,
a bell corresponding to each sprinkler would ring in an adjoining
room. On making a trial, the box was lowered upon the table,
and the temperature increased very slowly to 112 degrees, and
then the valve was opened and steam blown through the Parmelee
sprinkler head into the box. It required two minutes to increase
the temperature within the box one hundred degrees, and the circu-
lation of the steam was so rapid that thermometers inserted through
orifices in various parts of the box varied less than one degree from
each other. Although this was not the heat proceeding directly
from a fire yet it enabled the use of constant conditions, and the
results with any one sprinkler, as given in the record, do not vary
from each other more than would correspond to varying masses
of solder in the joint. "
Tests on sensitiveness showed the following time neces-
sary to open the different heads..
Bishop sensitive, with cup
Bishop sensitive, with sleeve
Brown sensitive .
Bishop sealed upright
Bishop sealed deflector
Burritt rose, open base
Burritt rose (hard solder)
Bursting Strength. The tests on bursting strength
showed a wide variation, the heads leaking at from 70
to 6000 pounds per square inch. Some of the heads
were new and some had been in use for 3 years or less.
AUTOMATIC SPRINKLER PROTECTION
Distribution. The tests on distribution showed that
under 3, 13, 22 and 36 pounds pressure the heads ranked
3 pounds per
13 pounds per
22 pounds per
36 pounds per
Bishop sealed de-
Bishop sealed de-
Grinnell placed up-
Grinnell placed up-
Grinnell placed up-
Bishop sealed de-
Bishop sealed de-
Discharge. The cubic feet of water discharged per
minute under 3, 20 and 50 pounds pressure including 5
feet of J-inch pipe and one elbow was as follows:
Burritt rose . .
Burritt open base
Bishop sealed .
TESTS AND CHARACTERISTICS OF SPRINKLERS 71
The following is also noted:
"Sealed sprinklers should not be connected directly to distributing
pipes, in the manner of valve sprinklers, because the circulation of
water after one sprinkler has opened is sufficient to cool the sprinkler
and prevent the prompt operation of the remaining sprinklers; and
it is only when placed at the ends of branch pipes in the proper
manner, that sealed automatic sprinklers should be approved for
protection against fire."
It might be well to describe here the low-fusing solder
used in automatic sprinklers as it has been practically
the same in all makes from the earliest heads to those
of modern times. Strange to say there has been prac-
tically no improvement in this detail of sprinkler con-
struction, perhaps because none was needed. It was
Sir Isaac Newton, in 1699, who first discovered that cer-
tain alloys possessed a lower melting point than their
constituents. He devised a mixture of bismuth 5 parts,
lead 3 parts, and tin 2 parts, which melted at 212 F.
Barnabas Wood of Nashville, Tenn., took out a
patent in 1860 upon which the composition of sprinkler
solder was afterwards based. The usual formula is:
Bismuth 4 parts
Lead ; 2 parts
Cadmium 1 part
Tin 1 part
This has a melting point of about 165 F., though
it granulates a few degrees lower. Woodbury in his
tests found that when a mass of this solder is cooled
slowly there will be a variation in the different portions
of the bar, due to the tendency of mixtures of metals
to separate into well-defined alloys.
He tested 19 samples of solder from nine manufac-
turers and found the melting points of the low-test solder
varied from 161 to 172 degrees. Solder cooled in ice
water began to soften at 6 degrees lower temperature
72 AUTOMATIC SPRINKLER PROTECTION
than when cooled slowly. He also found a variation
of from 2 to 26 degrees between the point at which
the solder softened and at which it actually melted.
By changing the proportions of the above formula
slightly, a melting point of 159.8 can be obtained. Lower
melting temperatures can be obtained by adding an
excess of bismuth but this makes the solder too brittle.
The above formula gives the lowest melting point that
is sufficiently hard, ductile and permanent for sprinkler
The melting points of the constituents are:
Cadmium 600 F.
Lead 504 F.
Bismuth 476 F.
Tin 421 F.
The matter of leakage from sprinkler heads has been
an important consideration ever since sprinklers were
first installed. It was frequently used as an argument
by mill owners against installing the device, and the
comparatively few cases where trouble did occur were
brought forward to support the argument. The matter
was investigated by the Factory Mutual Fire Insurance
Cos. in 1885. Letters were sent to plants equipped with
sprinklers and replies were received as follows:
Total number of replies received 224.
Number of leaks not due to accident 22
Number causing no damage 16
Number causing slight damage _J>
Number of leaks caused by accident 41
Number causing no damage 27
Number causing slight damage 14
41 , _
Total number of leaks 63
Many of the older heads developed slight leaks which
did no damage. A large part of these old heads were
TESTS AND CHARACTERISTICS OF SPRINKLERS 73
adjustable so that when they began to leak the valve
could readily be tightened.
A record of fires in buildings equipped with sprinklers
and buildings not so equipped was tabulated by the
same organization. In the sprinklered class only fires
starting in sections equipped with sprinklers were in-
cluded. The results were as follows:
Average loss per fire sprink-
lered buildings $1,081 (205 fires) $1,360
Average loss per fire unsprink-
lered buildings $17,613 (759 fires) $16,104
Mr. Woodbury states in his report that sprinklers of
the sensitive type cause less water damage than those
of the sealed type because fewer of the former operate.
Fire Record of Old Heads. The record of some of the
earlier types of sprinklers in actual fires between 1877
and 1885 was tabulated in his report as follows:
LATER MUTUAL TESTS
A second series of tests was made in 1886 and was
also in charge of Mr. Woodbury. The tests on sensitive-
ness were made by placing the heads in a building 20 by
30 feet and 10 feet high. Six sprinklers were installed
74 AUTOMATIC SPRINKLER PROTECTION
on piping near the roof, under a pressure of 35 to 40
pounds. They were subjected to heat from a fire con-
sisting of i barrel of shavings to which excelsior was
added if necessary. The time necessary to open the
different heads under these conditions was as follows:
Grinnell 1 minute, 4 seconds
Granger 1 minute, 33 seconds
Gunn 1 minute, 34 seconds
Star 4 minutes, 36 seconds
Kane (Excelsior) 6 minutes, 12 seconds
Walworth 6 minutes, 55 seconds
Braman Dow (Jordan) 7 minutes, 38 seconds
Buell, stuck in 3 cases out of 5.
Kane (reversible), stuck in 1 case out of 4.
The approved list of the Mutuals in 1886 included
the following: Grinnell, Buell, Kane, Walworth and
Gunn. Later the Clapp, Neracher and Hill heads were
added. Those approved in 1894- were: Grinnell, Hill,
Neracher, Clapp, Wm. Kane (all put in by the General
Fire Extinguisher Co.), Esty, Walworth, J. Kane, Newton
The heads approved by the New England Insurance
Exchange were as follows :
In 1892, Buell, Grinnell (metal and glass disc types),
Harkness, Hill, Kane, Neracher, Mackey, New York &
New Haven, Walworth.
In 1896 the Buell, Harkness, New York & New Haven
had been taken off the approved list and the Newton
and Esty added.
In 1900 the following heads had been added: Jahn,
Hibbard, Babcock and Universal.
List of approved sprinklers of the National Board of
Fire Underwriters, Jan., 1918:
TESTS AND CHARACTERISTICS OF SPRINKLERS 75
Crowder, A, Crowder Bros., St. Louis, Mo.
Esty, B, Esty Sprinkler Co., H. G. Vogel, sole agents,
New York City.
Globe, C, Globe Automatic Sprinkler Company,
Grinnell, Improved, General Fire Extinguisher Co.,
Providence, R. I.
Independent, A, Independent Min& Sprinkler Co.,
International, B, International Sprinkler Co., New
Lapham, B, Ohio Sprinkler Co., Yoiingstown, Ohio.
Manufacturers, C, Automatic Sprinkler Company
of America, New York City.
Neracher, Improved, General Fire Extinguisher Co.,
Providence, R. I.
Niagara, B, Automatic Sprinkler Co. of America,
New York City.
Rockwood, D, Rockwood Sprinkler Co., Worcester,
SIZE OF ORIFICE
The J-inch diaphragm or ring-nozzle outlet has been
taken for the standard and practically all sprinklers as
made today comply with this standard. A few heads
with 1-inch outlets, called jumbo heads, have been made
for use at the top of elevators and similar places but
these heads are much less sensitive and it is considered
better practice today to install several smaller ones in
place of one large head. There is a slight difference in
the discharge from the different makes of heads but the
following table gives a fair average.
AUTOMATIC SPRINKLER PROTECTION
DISCHARGE FROM SPRINKLERS
Failures from Age. The limit of life of a sprinkler
is something that is generally overlooked by the prop-
erty owner who puts in an equipment. It is quite
commonly assumed that so long as no fire occurs they
have no work to do and should last indefinitely. As a
matter of fact they are called upon to do work all the
time, namely, to hold back the water pressure in the