Page 76 - Facility Piping Systems Handbook for Industrial, Commercial, and Healthcare Facilities

PIPING

2.26 CHAPTER TWO

Joints could be tapered adhesive joints, bell and strape joints, or elastomeric compres-
sion type, depending on service. Dimensions must be obtained from the manufacturer.
FRP pipe shall conform to the following standards:
1. ASTM D 3262: Reinforced Plastic Sewer Pipe
2. ASTM D 3517: Reinforced Concrete Pressure Pipe
3. ASTM D 3839: Proper Installation of Composite Pipe

FITTINGS

Fittings are used to connect pipes to one another and to change the direction of
straight runs of pipe. An alternative to fittings is bending the pipe to allow changes in
direction.

CODE CONSIDERATIONS

Codes require that any change in direction of plumbing piping in a drainage system be
made with fittings. The fittings shall have long radius bends so as not to allow solids any
place to accumulate and to provide good hydraulic flow characteristics. These are known
as drainage pattern fittings, and they are required to be used for drainage systems. Threaded
drainage fittings shall be of the recessed type. Drainage pattern fittings are not required to
be used for vent piping. Pressure systems can use any fitting type.

FITTING TYPES

A small number of fittings used either singly or in combination with one another are the
most commonly used.

1. Bends or sweeps are used to change the direction of a pipe. These fittings come in vari-
ous angles. A 3/4 bend is a 90° fitting, and comes either as a short or long sweep (or
radius). A 1/8 bend is a 45° angle and a 1/16 bend is a 22.5° angle.
2. The wye is used to connect a branch pipe into a straight run of piping at a 45° angle.
These fittings are available with either all similar sizes or various combinations of pipe
sizes in any connection.
3. The tee fitting is used to connect a branch pipe into a straight run of piping at a right
angle, where the flow characteristic of liquid is not a factor. These fittings are available
with either all similar sizes or various combinations of pipe sizes in any combination.
4. The elbow is a 90° change of direction with a very short radius. They are available with
either all similar sizes or combinations of pipe sizes.

Refer to Fig. 2.3 for an illustration of these four basic types of fittings. In addition
to those discussed here, there is a large variety of special combination drainage fittings
manufactured for use either where space considerations are of primary importance or where
combination fittings will result in considerable savings in time and labor.

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