A328.4 Preparation for Bonding
Preparation shall be defined in the BPS and shall specify
such requirements as
(a) cutting
(b) cleaning
(c) preheat
(d) end preparation
(e) fit-up
A328.5 Bonding Requirements
A328.5.1 General
(a) Production joints shall be made only in accordance
with a written bonding procedure specification (BPS) that
has been qualified in accordance with para. A328.2. Manufacturers
of piping materials, bonding materials, and
bonding equipment should be consulted in the preparation
of the BPS.
(b) Production joints shall be made only by qualified
bonders or bonding operators who have appropriate
training or experience in the use of the applicable BPS
and have satisfactorily passed a performance qualification
test that was performed in accordance with a qualified
BPS.
(c) Each qualified bonder and bonding operator shall
be assigned an identification symbol. Unless otherwise
specified in the engineering design, each pressurecontaining
bond or adjacent area shall be stenciled or
otherwise suitably marked with the identification
symbol of the bonder or bonding operator. Identification
stamping shall not be used and any marking paint or ink
shall not be detrimental to the piping material. In lieu of
marking the bond, appropriate records may be filed.
(d) Qualification in one BPS does not qualify a bonder
or bonding operator for any other bonding procedure.
(e) Longitudinal joints are not covered in para. A328.
A328.5.2 Hot Gas Welded Joints in Thermoplastic
Piping5
(a) Preparation. Surfaces to be hot gas welded together
shall be cleaned of any foreign material. For butt welds, the
joining edges should be beveled at 20 deg to 40 deg with 1
mm (1∕32 in.) root face and root gap.
(b) Procedure. Joints shall be made in accordance with
the qualified BPS.
(c) Branch Connections. A fabricated branch connection
shall be made by inserting the branch pipe in the hole in
the run pipe. Dimensions of the joint shall conform to
Figure 328.4.3-1, illustration (c). The hole in the run
pipe shall be beveled at 45 deg. Alternatively, a fabricated
branch connection shall be made using a manufactured
full reinforcement saddle with integral socket.
A328.5.3 Solvent Cemented Joints in Thermoplastic ð24Þ
Piping5
(a) Preparation. Thermoplastic pipe and fitting
surfaces shall be prepared in accordance with ASTM
D2855 or ASME NM.1, para. 5-3.5 for PVC, ASTM F493
or ASME NM.1, para. 5-3.5 for CPVC, or ASTM D2235
for ABS. A dry fit test of each joint is required before
solvent cementing. The pipe shall enter the fitting
socket between one-third and two-thirds of the full
socket depth when assembled by hand.
(b) Procedure. Joints shall be made in accordance with
the qualified BPS. ASTM D2855 or ASME NM.1, para. 5-3.5
may be utilized as a suitable basis for development of such
a procedure. Solvent cements for PVC, CPVC, and ABS shall
conform to ASTM D2564, ASTM D2846, and ASTM D2235,
respectively. Application of cement to both surfaces to be
joined and assembly of these surfaces shall produce a
continuous bond between them with visual evidence of
cement at least flush with the outer end of the fitting
bore around the entire joint perimeter. See Figure
A328.5.3-1.
(c) Branch Connections. A fabricated branch connection
shall be made using a manufactured full reinforcement
saddle with integral branch socket. The reinforcement
saddle shall be solvent cemented to the run pipe over
its entire contact surface.
A328.5.4 Heat Fusion Joints in ThermoplasticPiping5 ð24Þ
(a) Preparation. Surfaces to be heat fused together shall
be cleaned of all foreign material.
(b) Procedure. Joints shall be made in accordance with
the qualified fusing procedure specification (FPS). Procedure
1, Socket Fusion, Procedure 2, Butt Fusion, and
Procedure 3, Saddle Fusion, in both ASTM F2620 and
ASTM D2657, provide a suitable basis for development
of such a procedure. Uniform heating of both surfaces
to be joined and assembly of these surfaces shall
produce a continuous homogeneous bond between
them and shall produce a small fillet of fused material
at the outer limits of the joint. See Figure A328.5.4-1
Figure A328.5.3-1
Thermoplastic Solvent Cemented Joint
Socket Joint
APPENDIX G
SAFEGUARDING
ð24Þ G300 SCOPE
(a) Safeguarding is the provision of protective
measures to minimize the risk of accidental damage to
the piping or to minimize the harmful consequences of
possible piping failure.
(b) In most instances, the safeguarding inherent in the
facility (the piping, the plant layout, and its operating practices)
is sufficient without need for additional safeguarding.
In some instances, however, additional
engineering safeguards are required.
(c) Appendix G outlines some considerations
pertaining to the selection and utilization of safeguarding.
Where safeguarding is required by the Code, it is necessary
to consider only the safeguarding that will be suitable
and effective for the purposes and functions stated in the
Code or evident from the designer’s analysis of the application.
G300.1 General Considerations
In evaluating a piping installation design to determine
what safeguarding may exist or is necessary, the following
should be reviewed:
(a) the hazardous properties of the fluid, considered
under the most severe combination of temperature, pressure,
and composition in the range of expected operating
conditions.
(b) the quantity of fluid that could be released by piping
failure, considered in relation to the environment, recognizing
the possible hazards ranging from large releases of
otherwise innocuous fluids to small leakages of toxic
fluids.
(c) expected conditions in the environment, evaluated
for their possible effect on the hazards caused by a
possible piping failure. This includes consideration of
ambient or surface temperature extremes, degree of ventilation,
proximity of fired equipment, etc.
(d) the probable extent of operating, maintenance, and
other personnel exposure, as well as reasonably probable
sources of damage to the piping from direct or indirect
causes.
(e) the probable need for grounding of static charges to
prevent ignition of flammable vapors.
(f) the safety inherent in the piping by virtue of materials
of construction, methods of joining, and history of
service reliability.
G300.2 Safeguarding by Plant Layout and
Operation
Representative features of plant layout and operation
that may be evaluated and selectively utilized as safeguarding
include
(a) plant layout features, such as open-air process
equipment structures; spacing and isolation of hazardous
areas; slope and drainage; buffer areas between plant
operations and populated communities; or control over
plant access
(b) protective installations, such as fire protection
systems; barricades or shields; ventilation to remove
corrosive or flammable vapors; instruments for remote
monitoring and control; containment and/or recovery
facilities; or facilities (e.g., incinerators) for emergency
disposal of hazardous materials
(c) operating practices, such as restricted access to
processing areas; work permit system for hazardous
work; or special training for operating, maintenance,
and emergency crews
(d) means for safe discharge of fluids released during
pressure relief device operation, blowdown, cleanout, etc.
(e) procedures for startup, shutdown, and management
of operating conditions, such as gradual pressurization
or depressurization, and gradual warmup or
cooldown, to minimize the possibility of piping failure,
e.g., brittle fracture
G300.3 Engineered Safeguards
Engineered safeguards that may be evaluated and selectively
applied to provide added safeguarding include
(a) means to protect piping against possible failures,
such as
(1) thermal insulation, shields, or process controls to
protect from excessively high or low temperature and
thermal shock
(2) armor, guards, barricades, or other protection
from mechanical abuse
(3) damping or stabilization of process or fluid flow
dynamics to eliminate or to minimize or protect against
destructive loads (e.g., severe vibration pulsations, cyclic
operating conditions)
(b) means to protect people and property against
harmful consequences of possible piping failure, such
as confining and safely disposing of escaped fluid by