# CH-IV — Pipeline Safety Interpretation

- **operation:** document
- **citation:** PI-21-0009
- **title:** CH-IV — Pipeline Safety Interpretation
- **source type:** guidance
- **agency:** Pipeline and Hazardous Materials Safety Administration
- **status:** guidance
- **official:** true
- **published on:** 2021-10-07
- **effective on:** Not available
- **summary:** PI-21-0009 response to CH-IV concerning 193.2303.
- **machine formats:** - **json:** https://regulus.evalyn.ai/document/phmsa-interpretation-pi-21-0009.json
- **markdown:** https://regulus.evalyn.ai/document/phmsa-interpretation-pi-21-0009.md
- **app url:** https://regulus.evalyn.ai/document/phmsa-interpretation-pi-21-0009
- **source url:** https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/docs/standards-rulemaking/pipeline/interpretations/75986/ch-iv-pi-21-0009-10-07-2021-part193-2303.pdf
**body:**

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U.S. Department
of Transportation
Pipeline and Hazardous
Materials Safety Administration October 7, 2021
1200 New Jersey Avenue, SE
Washington, DC 20590
Mr. Juan Carlos Rivadeneira
Engineer
CH-IV
1221 McKinney, Suite 3333
Houston, TX 77010
Dear Mr. Rivadeneira:
In a letter to the Pipeline and Hazardous Materials Safety Administration (PHMSA), dated
August 19, 2021, you requested an interpretation of the minimum pipeline welding inspection
and testing requirements for piping systems and components for flammable liquids and
flammable gases with service temperatures above −20 degrees Fahrenheit (°F) (−29 °Centigrade
(C)) to comply with 49 Code of Federal Regulations (CFR) § 193.2303. Specifically, you sought
confirmation that for these piping systems and components to comply with § 193.2303, a
minimum of 30 percent of each day’s circumferentially welded pipe joints must be
nondestructively tested over the entire circumference.
Section 193.2303 incorporates by reference the 2001 edition of National Fire Protection
Association Standard 59A (NFPA 59A-2001), and Chapter 6 of NFPA 59A-2001 specifies
requirements for piping systems and components. While paragraph 6.1.1 of NFPA 59A-2001
requires that all piping systems comply with the 1996 Edition of ASME B31.3, it further states
that the additional provisions of Chapter 6 of NFPA 59A-2001 shall apply to piping systems and
components for flammable liquids and flammable gases with service temperatures below −20 °F
(−29 °C). The provision found in paragraph 6.6.3.2 of NFPA 59A-2001, which requires that all
circumferential butt welds be examined fully by radiographic or ultrasonic inspection, contains
an exception for pressure piping operating above −20 °F (−29 °C). Specifically, Exception No. 2
to paragraph 6.6.3.2 states:
Pressure piping operating above −20 °F (−29 °C) shall have 30 percent of each day’s
circumferentially welded pipe joints nondestructively tested over the entire circumference
in accordance with ASME B31.3.
Moreover, paragraph 341.4.1(b)(1) of ASME B31.3 requires that not less than 5 percent of
circumferential butt and miter groove welds be examined fully by random radiography in
accordance with paragraph 344.5 or by random ultrasonic examination in accordance with
paragraph 344.6. However, performing a minimum of 5 percent of examination per ASME
B31.3 does not meet the requirements in NFPA 59A-2001. Instead, an operator shall have 30
The Pipeline and Hazardous Materials Safety Administration, Office of Pipeline Safety provides written clarifications of the Regulations (49 CFR
Parts 190-199) in the form of interpretation letters. These letters reflect the agency's current application of the regulations to the specific facts
presented by the person requesting the clarification. Interpretations do not create legally-enforceable rights or obligations and are provided to
help the public understand how to comply with the regulations.

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percent testing for each day’s circumferentially welded pipe joints in accordance with NFPA
59A-2001.
Therefore, PHMSA agrees with your interpretation of the NFPA 59A-2001 requirements that for
flammable liquids and flammable gases with service temperatures above −20 °F (−29 °C) to
comply with § 193.2303, a minimum of 30 percent of each day’s circumferentially welded pipe
joints must be nondestructively tested over the entire circumference.
If we can be of further assistance, please contact Tewabe Asebe at 202-366-5523.
Sincerely,
John A. Gale
Director, Office of Standards
and Rulemaking
The Pipeline and Hazardous Materials Safety Administration, Office of Pipeline Safety provides written clarifications of the Regulations
(49 CFR Parts 190-199) in the form of interpretation letters. These letters reflect the agency's current application of the regulations to the
specific facts presented by the person requesting the clarification. Interpretations do not create legally-enforceable rights or obligations and
are provided to help the public understand how to comply with the regulations.

<<<PAGE 3>>>

Contact Name: Juan Carlos Rivadeneira Title: Engineer
Direct Line: 713-964-6775
Direct Email: jcrivadeneira@ch-iv.com
1221 McKinney, Suite 3333
Houston, TX 77010 USA
www.CH-IV.com
August 19, 2021
Mr. John A. Gale
Director, Office of Standards and Rulemaking
Office of Pipeline Safety (PHP-30)
Pipeline and Hazardous Materials Safety Administration
U.S. Department of Transportation
1200 New Jersey Avenue, S.E.
Washington, D.C. 20590-0001
Title 49 of the Code of Federal Regulations Interpretation of Part 193, Section 193.2303
Dear Mr. Gale,
This letter is a formal request for written interpretation of the referenced section of Title 49 of the Code of
Federal Regulations Part 193. This interpretation is requested to clarify the minimum inspection and testing
requirements for piping systems and components for flammable liquids and flammable gases with service
temperatures above −20°F (−29°C) to comply with §193.2303.
§193.2303 states:
“No person may place in service any component until it passes all applicable inspections and tests
prescribed by this subpart and NFPA-59A-2001 (incorporated by reference, see §193.2013).”
NFPA-59A-2001 Chapter 6 provides requirements for inspection and testing for piping systems used in
LNG facilities. In particular, NFPA-59A-2001 Section 6.1.1 states:
“All piping systems shall be in accordance with ASME B31.3, Process Piping. The additional provisions of
this chapter shall apply to piping systems and components for flammable liquids and flammable gases with
service temperatures below −20°F (−29°C).
Exception: Fuel gas systems covered by NFPA 54, National Fuel Gas Code.”
From NFPA-59A-2001 Section 6.1.1, it is understood that all piping systems in the LNG facility have to
meet the requirements of ASME B31.3, regardless of their operating conditions and service. NFPA-59A-
2001 Section 6.1.1 specifically notes that the additional provisions in Chapter 6 apply to piping systems and
components for flammable liquids and flammable gases with service temperatures below −20°F (−29°C).
Therefore, it is implied that Section 6.1.1 does not apply to piping systems and components for flammable
liquids and flammable gases with service temperatures above −20°F (−29°C) and these shall meet the
requirements of ASME B31.3 only.
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NFPA-59A-2001 Section 6.6.3.2 provides requirements for nondestructive examination of applicable piping
systems covered by Chapter 6. NFPA-59A-2001 Section 6.6.3.2 states:
“All circumferential butt welds shall be examined fully by radiographic or ultrasonic inspection.
Exception No. 1: Liquid drain and vapor vent piping with an operating pressure that produces a hoop stress
of less than 20 percent specified minimum yield stress shall not be required to be nondestructively tested
if it has been inspected visually in accordance with ASME B 31.3, Process Piping, Section 344.2.
Exception No. 2: Pressure piping operating above −20°F (−29°C) shall have 30 percent of each day’s
circumferentially welded pipe joints nondestructively tested over the entire circumference in accordance
with ASME B 31.3.”
Note that Exception No. 2 in NFPA-59A-2001 Section 6.6.3.2 specifies that piping systems operating above
−20°F (−29°C) shall have 30 percent of each day’s circumferentially welded pipe joints nondestructively
tested over the entire circumference in accordance with ASME B31.3. Therefore, it is understood that
NFPA-59A-2001 Section 6.6.3.2 Exception No. 2 modifies the requirements of Section 6.1.1. This is
supported by the fact that ASME B31.3 Section 341.4.1(b)(1) states:
“Not less than 5% of circumferential butt and miter groove welds shall be examined fully by random
radiography in accordance with para. 344.5 or by random ultrasonic examination in accordance with para.
344.6...”.
Thus, it is understood that for piping systems and components for flammable liquids and flammable gases
with service temperatures above −20°F (−29°C) to comply with §193.2303, a minimum of 30 percent of
each day’s circumferentially welded pipe joints shall be nondestructively tested over the entire
circumference and that performing the minimum of 5 percent examination per ASME B31.3 Section
341.4.1(b)(1) does not meet the requirements of §193.2303.
We would like to confirm that for piping systems and components for flammable liquids and flammable
gases with service temperatures above −20°F (−29°C) to comply with §193.2303, a minimum of 30 percent
of each day’s circumferentially welded pipe joints shall be nondestructively tested over the entire
circumference.
Looking forward to your feedback, I am available for future discussions as needed. Thank you for handling
this matter and I look forward to hearing from you soon.
Sincerely,
JUAN CARLOS RIVADENEIRA
Engineer
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