Page 57 - Facility Piping Systems Handbook for Industrial, Commercial, and Healthcare Facilities

PIPING

PIPING 2.7

2. ASTM B-819 is similar to B-88, except that it is available only in grades K and L and, in
addition, the pipe is factory cleaned, capped, and specially marked. This pipe is required
to be used for medical gas systems in health-care facilities. It should also be considered
as the primary copper pipe for gases in laboratories as well.
3. ASTM B-75 is seamless, available as either hard or drawn, and in nominal sizes from
1/8- to 2-in O.D. The smaller sizes are often referred to as capillary tubing. This is the
grade most often used for very small diameter pipe [1/4-in O.D. (6 mm) or less] con-
necting instruments to the distribution piping. This pipe is commonly joined by patented
flare joints, which require temper 060 to seal correctly.
4. ASTM B-280, type ACR (air conditioning and refrigeration), is available cleaned and
capped for field refrigeration piping and could also be considered for laboratory use. It is
available only in hard temper, and its size is the actual O.D. of the pipe. This requires that
all non-ACR fittings used in the system, which are manufactured in nominal pipe size, be
dimensionally compatible with the ACR pipe, which is manufactured in actual pipe size.
5. ASTM B-306, copper drainage tube, is known as DWV (drainage, waste, and vent).
This designation applies to copper tube used for nonpressure drainage systems. This
tube has the thinnest wall of any copper product. The preferred jointing method is sol-
dering, which is adequate in strength and the least costly. Primary use is in residential
construction as indirect waste lines and in larger projects for local branch lines where
human waste is not discharged. Advantages are its light weight, ease of assembly, and
smooth interior. Disadvantages include corrosive attack by ordinary sewage, poor fire
resistance, and the need for dielectric connections to eliminate galvanic corrosion where
this material is connected to any iron piping.
6. ASTM B-837 Type G is seamless tube, available in either hard (drawn) or soft (annealed)
temper, and in nominal sizes from 3/8- to 1/8 -in O.D. This tubing is identified by the
O.D. rather than nominal size. This grade is manufactured specifically for natural gas
and LP fuel gas systems. Fittings shall be similar to those used with type ACR copper.
The pipe is joined by either brazing or flare type joints. Brazed joints are required for
system pressures above 14-in WC where installed in inaccessible locations. Brazing
alloys shall contain less than 0.05 percent phosphorus.

DUCTILE IRON PIPE (DI)

Ductile iron is a cast ferrous material alloyed with free nodular or spheroidal graphite in
lieu of the flakes that are present in cast iron. This is achieved by the addition of a magne-
sium inoculant. It is used either as a gravity sewer or pressure pipe. Sizes available range
from 3 to 54 in. There are eight pressure ratings—class 50 (125 psi) to class 56 (350 psi),
and gravity sewer pipe. A cement or bituminous lining can be provided to resist internal
corrosion. This pipe can be assembled with mechanical, gasketed, or flanged joints. Ductile
iron pipe shall conform to ASTM A 518 and ASTM A 861.
The advantages of ductile iron are the same as those for CI pipe, except that it is far
stronger in terms of allowable pressure ratings and external load-bearing capacity. It is also
not as brittle, allowing rougher handling. It has a higher initial cost than CI.

LEAD (LD)

Lead pipe is made from 99.7% pig lead with various alloys available for special applica-
tions. Joints for this pipe are either wiped, burned, or mechanically flanged. Lead pipe shall
conform to WW-P-325a: Lead Pipe, Bends, and Traps.

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