1|Page
API RP 574 4 Piping Components Questions and Answers
with 100% Complete Solutions UPDATED!!!
4.1 - ANSWER Piping
4.1.1 General - ANSWER Piping can be made from any material
that can be rolled and welded, cast, or drawn through dies to
form a tubular section. The two most common carbon steel
piping materials used in the petrochemical industry are ASTM
A53/A53M and ASTM A106. The industry uses both seamless
and electric resistance welded (ERW) piping for process
services, depending upon current economics and the potential
for accelerated corrosion of the weld seam in the service. Piping
of a nominal size larger than 16" (406mm) is usually made by
rolling plates to size and welding the seams. Centrifugally cast
piping can be cast then machined to any desired thickness.
Steel and alloy piping are manufactured to standard dimensions
in nominal pipe sizes (NPSs) up to 48" (1219mm)
Pipe wall thicknesses are designated as pipe schedules in NPSs
up to 36" (914mm). The traditional thickness designations---
standard weight, extra strong, and double extra strong---differ
from schedules and are used for NPSs up to 48" (1219mm). In
all standard sizes, the outside diameter (OD) remains nearly
constant regardless of the thickness. The size refers to the
,2|Page
approximate inside diameter (ID) of standard weight pipe for
NPSs equal to or less than 12" (305mm). The size denotes the
actual OD for NPSs equal to or greater than 14" (356mm). The
pipe diameter is expressed as NPS, which is based on these size
practices. Table 1 and Table 2 list the dimensions of ferritic and
stainless steel pipe from NPS 1/8 [DN (nominal diameter) 6] up
through NPS 24 (DN 600). See ASME B36. 10M for the
dimensions of welded and seamless wrought steel piping and
ASME B36.19M for the dimensions of stainless steel piping.
Allowable tolerances in pipe diameter differ from one piping
material to another. Table 3 lists the acceptable tolerances for
diameter and thickness of most ASTM ferritic pipe standar
4.1.2 FRP Pipe - ANSWER Nonmetallic materials also have some
limited uses in piping systems in the hydrocarbon process
industry. They have significant advantages over more familiar
metallic materials, but they also have unique construction and
deterioration mechanisms that can lead to premature failures if
not addressed adequately.
The term nonmetallic has a broad definition but in this section
refers to the fiber reinforced plastic groups encompassed by the
generic acronym FRP and GRP (glass reinforced plastic). The
extruded, generally homogenous nonmetallics, such as high-
, 3|Page
and low-density polyethylene, are excluded from coverage in
this document but are also used in some utility and specialty
services.
Typical service applications of FRP piping include service water,
process water, cooling medium, potable water, sewage/gray
water, nonhazardous waste, nonhazardous drains,
nonhazardous vents, chemicals, firewater ring mains, firewater
deluge systems, and produced and ballast water.
Design of these piping systems is largely dependent on the
application. Many companies have developed their own
specifications that outline the materials, quality, fabrication
requirements, and design factors. ASME B31.3, Chapter VII
covers design requirements for nonmetallic piping. American
Water Works Association (AWWA) is an organization that also
provides guidance on FRP pipe design and testing. These codes
and standards, however, do not offer guidance as to the right
choice of corrosion barriers, resins fabricating methods, and
joint systems for a particular application. The user should
consider other sources such as resin and pipe manufacturers for
guidance on their particular application.
API RP 574 4 Piping Components Questions and Answers
with 100% Complete Solutions UPDATED!!!
4.1 - ANSWER Piping
4.1.1 General - ANSWER Piping can be made from any material
that can be rolled and welded, cast, or drawn through dies to
form a tubular section. The two most common carbon steel
piping materials used in the petrochemical industry are ASTM
A53/A53M and ASTM A106. The industry uses both seamless
and electric resistance welded (ERW) piping for process
services, depending upon current economics and the potential
for accelerated corrosion of the weld seam in the service. Piping
of a nominal size larger than 16" (406mm) is usually made by
rolling plates to size and welding the seams. Centrifugally cast
piping can be cast then machined to any desired thickness.
Steel and alloy piping are manufactured to standard dimensions
in nominal pipe sizes (NPSs) up to 48" (1219mm)
Pipe wall thicknesses are designated as pipe schedules in NPSs
up to 36" (914mm). The traditional thickness designations---
standard weight, extra strong, and double extra strong---differ
from schedules and are used for NPSs up to 48" (1219mm). In
all standard sizes, the outside diameter (OD) remains nearly
constant regardless of the thickness. The size refers to the
,2|Page
approximate inside diameter (ID) of standard weight pipe for
NPSs equal to or less than 12" (305mm). The size denotes the
actual OD for NPSs equal to or greater than 14" (356mm). The
pipe diameter is expressed as NPS, which is based on these size
practices. Table 1 and Table 2 list the dimensions of ferritic and
stainless steel pipe from NPS 1/8 [DN (nominal diameter) 6] up
through NPS 24 (DN 600). See ASME B36. 10M for the
dimensions of welded and seamless wrought steel piping and
ASME B36.19M for the dimensions of stainless steel piping.
Allowable tolerances in pipe diameter differ from one piping
material to another. Table 3 lists the acceptable tolerances for
diameter and thickness of most ASTM ferritic pipe standar
4.1.2 FRP Pipe - ANSWER Nonmetallic materials also have some
limited uses in piping systems in the hydrocarbon process
industry. They have significant advantages over more familiar
metallic materials, but they also have unique construction and
deterioration mechanisms that can lead to premature failures if
not addressed adequately.
The term nonmetallic has a broad definition but in this section
refers to the fiber reinforced plastic groups encompassed by the
generic acronym FRP and GRP (glass reinforced plastic). The
extruded, generally homogenous nonmetallics, such as high-
, 3|Page
and low-density polyethylene, are excluded from coverage in
this document but are also used in some utility and specialty
services.
Typical service applications of FRP piping include service water,
process water, cooling medium, potable water, sewage/gray
water, nonhazardous waste, nonhazardous drains,
nonhazardous vents, chemicals, firewater ring mains, firewater
deluge systems, and produced and ballast water.
Design of these piping systems is largely dependent on the
application. Many companies have developed their own
specifications that outline the materials, quality, fabrication
requirements, and design factors. ASME B31.3, Chapter VII
covers design requirements for nonmetallic piping. American
Water Works Association (AWWA) is an organization that also
provides guidance on FRP pipe design and testing. These codes
and standards, however, do not offer guidance as to the right
choice of corrosion barriers, resins fabricating methods, and
joint systems for a particular application. The user should
consider other sources such as resin and pipe manufacturers for
guidance on their particular application.
