The New York herald., 1921-10-16
WOOLWORTH BLDG.
AN AID TOSCIENCE
Piping Tall Structure Resulted
in Cutting Building Costs,
Says Engineer.

ripping tne w NOOiWOrtn bullulnB re-
quired research which resulted In ma
terially lessening, skyscraper building
costs as well as discovering safe use
Of ammonia gas. according to Edward
ing at Massachusetts, Institute of Tech
nology, who, in a bulletin just issued
by the Engineering Foundation, ac-
lively engaged In fostering research In
this country, asserts that 'the necessity
for research often arises In the or
dinary practice of engineering"
Research does not always involve
tedious experimentation" Prof. Miller
says. when helpful knowledge Of for
mer research is available and men CO.
operate problems are sometimes quickly
solved. The solution Of a problem for
one purpose may be useful in many
others II properly recorded. But records
to be useful must be accessible The
technical and scientific societies and
Journals and our libraries can be help
full If utilized also the Research Infor-
nation Service of the National Research
Council.
Ammonia in some forms is with
impunity used daily for many house,
hold purposes, but ammonia gas In
quantity Is deadly" Prof. Miller con-
tinues: Nevertheless, this gas is ex-
tensiveIy employed for refrigerating
and other processes. 1t may be safely
used If rightly controlled. Some years
ago many fatal accidents occurred due
to safety valves on ammonia pipes dis
charging the gas into operating rooms Of
refrigerating plants, hotels and manu-
featuring establishments. AS a conse-
| quence Massachusetts and New York
passed laws requiring safety valves to
have O discharge pipe through the roof
Of the building. the pipe to extend ten
feet above the roof, IL the adjoining
building was higher.
WOODWORK Building Tests.
.In New York one Of the first prob
lens encountered under the new law was
the piping in the many storied Wool
worth Building on lower Broadway.
There were but few data available by
which the size Of the ammonia dis
charge pipe could be figured, because
little was known about the difference
of pressure required to put given guam
tity Of superheated ammonia gas
through long pipe. the pipe being open
to the air at one end. Experiments
we're then made to deducc formula
for the flow of ammonia gas in q pipe
open to the air. What quantity would
flow through pipe Of given length and
diameter, under a given pressure at the
entrance end Of the pipe? Similar ex-
periments were made on the discharge
Of steam. From these data It became
evident that two-inch safety valve had
to have a six-inch pipe to discharge
even with five pounds pressure above
the atmosphere at the entrance OF the
pipe, the quantity OF ammonia gas that
would pass through the two-inch safety
valve.
'vrhe old Idea then came Into the
minds of two engineers working on the
problem that the flow of steam from
275 pounds absolute pressure into the
air was practically the same In guam
tity as the flow of steam at 275 pounds
absolute pressure into chamber where
the pressure was $50 pounds absolute.
This led to the design OF an ammonia
safety valve discharging against back
DTeSSuIG.
the upper limit OF back pressure that
an ammonia valve could discharge
against?
Discovery That Meant Economy.
"Other series Of tests were made to
determine this minimum pressure. 1t
was found that the flow into a reservoir
where the back pressure was 0.5S5 times
the entrance pressure (that Is, some-
what more than half the entrance pres
sure) was exactly the same as the flow
into a reservoir where the pressure was
atmospheric. AS a result, a safety valve
was designed which would discharge
against back pressure. Tests on this
valve showed that the theory was cor
rect. Ammonia safety valves as built
to-day are capable OF discharging
against this high back pressure.
This, of course. means that the dis
charge pipe In cases like that men,
toned, instead Of being six inches In
diameter can be Of a very much smaller
size, since the entrance pressure In this
pipe Is now approximately $50 pounds
instead of five pounds above the atmos-
phere. The resulting economy and con-
venience are obvious as well as the sat
isfactory solution Of this detail problem