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Certificate 7726

Downloadable version

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Safety and Security

Transport Dangerous
Goods Directorate
330 Sparks Street
Ottawa, Ontario K1A 0N5
Sécurité et sûreté

Direction générale du
transport des marchandises dangereuses
330, rue Sparks
Ottawa (Ontario) K1A 0N5

Equivalency Certificate

Certificate No.: SU 7726 (Ren. 3)

Certificate Holder: Norris Cylinder Company

Mode of Transport: Road, Rail, Air, Marine

Issue Date: August 27, 2014

Expiry Date: August 31, 2019


This Equivalency Certificate authorizes Norris Cylinder Company to sell, offer for sale, distribute, or deliver in Canada, and authorizes any person to handle, offer for transport, transport, or import into Canada, by road or railway vehicle, by aircraft or by ship on a domestic voyage, cylinders in a manner that does not comply with sections 5.1 and 5.2, subparagraphs 5.10(1)(a)(ii), 5.10(1)(b)(iii), 5.10(1)(c)(ii), 5.10(1)(d)(iii), and subsection 5.10(2) of the Transportation of Dangerous Goods Regulations, if:

Selection and Use

(a) subject to condition (b), the requirements applicable to Specification

TC-3AAM cylinders in CSA Standard B340-08, "Selection and use of cylinders, spheres, tubes, and other containers for the transportation of dangerous Goods, Class 2", March 2008, are complied with;

Equivalency Certificate

SU 7726 (Ren. 3)


(b) each cylinder contains one of the following dangerous goods:

Dangerous Goods PIN

AIR, compressed, with not more than UN1002

23.5 per cent oxygen, by volume

Argon, compressed UN1006

Helium, compressed UN1046

Nitrogen, compressed UN1066

Oxygen, compressed UN1072


(c) the cylinders are manufactured at 4818 West Loop 281, Longview, Texas, in accordance with the specific procedures and with drawing No. 901A-A-9624 filed by Norris Cylinder Company with the Transport Dangerous Goods Directorate;

(d) subject to conditions (e) to (v), the cylinders are in compliance with the requirements applicable to specification TC-3AAM set out in CSA Standard B339-08, "Cylinders, spheres, and tubes for the tansportation of dangerous goods", March 2008, cited in the rest of this certificate as CSA B339-08;

(e) the chemical composition of the steel cylinder corresponds to the chemical composition set out in Table I of Appendix A to this certificate;

(f) the steel is fully killed and made by a fine grain de-oxidation practice;

(g) the cylinders are manufactured by the backward extrusion process, have bottoms with a thickness not less than the cylinder sidewall thickness, and have a surface finish which does not exceed a roughness of 250 root mean square;

(h) for cylinders with a service pressure of 6.9 MPa or more, the wall stress in Equation 1, Clause 4.2.1 of CSA B339-08, does not exceed 67 per cent of the minimum tensile strength as determined by the tensile test or 624 MPa, whichever is the lesser;

Equivalency Certificate

SU 7726 (Ren. 3)


(i) cylinders are held at the austenitizing temperature for at least 2.4 minutes for each millimetre of maximum cylinder thickness and are then quenched in a liquid medium which provides a cooling rate not greater than 80 per cent of that of water, and

(i) the steel temperature on quenching does not exceed 927°C, and

(ii) the tempering temperature is not less than 565°C, and the cylinders are held at that tempering temperature for at least 2.4 minutes for each millimetre of maximum cylinder thickness;

(j) the hydrostatic testing with determination of volumetric expansion is performed by the water jacket method;

(k) despite the flattening test requirements specified in Clause 6.10.4 of CSA B339-08, flattening to 8 times the wall thickness without cracking is required, and the Inspector records the actual degree of flattening attained without cracking;

(l) three (3) Charpy impact specimens, taken from one heat treated cylinder for each lot of 200 cylinders or less, are tested, and

(i) each specimen is a V-notch type size 10 x 4 mm or the largest obtainable taken in accordance with ASTM standard E 23-06, Standard Test Methods for Notched Bar Impact Testing and Metallic Material, published in 2007,

(ii) each specimen is taken from the sidewall of the cylinder,

(iii) the axis of the specimen is perpendicular to the longitudinal axis of the cylinder, and the axis of the notch is perpendicular to the surface of the cylinder, and

(iv) the impact properties for the specimens tested at - 50°C are not less than:

Size (mm)

Average Value

for 3 Specimens, minimum

Minimum Value for 1 specimen

10.0 X 4.0

17 Joules

14 Joules

Equivalency Certificate

SU 7726 (Ren. 3)


(m) a hardness test is performed on the cylindrical section of each cylinder after heat treatment, and the hardness does not exceed HRc35, and when the result of the initial hardness test exceeds the maximum permitted, two or more retests may be made but the hardness number obtained in each retest cannot exceed the maximum permitted;

(n) a flawed cylinder test is performed on one heat treated cylinder taken from each lot of 200 cylinders or less. A flaw is introduced into the test cylinder by a means that will not affect the mechanical or metallurgical properties such as, by the standard Charpy V-notch cutter, and

(i) each flaw is at least 6 times the wall thickness in length and located at approximately the mid-length of the cylindrical part of the cylinder,

(ii) cycling is carried out as described in clause 4.14.4 of CSA B339-08, except that the pressure is cycled between 0 kPa and 1.25 times the service pressure, and cycling is continued to cylinder failure, and

(iii)failure is by leakage before burst with evidence of crack propagation by fatigue prior to leakage;

(o) tensile strength, as determined by the tensile test, is not more than 1069 MPa, and elongation is at least 16 per cent for a 50.8 mm gauge length with width not over 38.1 mm;

(p) each cylinder is non-destructively inspected for flaws after heat treatment by one of the following methods:

(i) the wet magnetic particle method in accordance with ASTM Standard E 709-08, Standard Guide for Magnetic Particle Testing, published in 2008. Any cylinder that has a quenching crack is condemned,

Equivalency Certificate

SU 7726 (Ren. 3)


(ii) the ultrasonic inspection method in accordance with ASTM E213-09, Standard Practice for Ultrasonic Testing of Metal Pipe and Tubing, published in 2009. Ultrasonic Inspectors are qualified to National Standard of Canada CAN/CGSB‑48.9712, Non-Destructive Testing - Qualification and Certification of Personnel, published in 2006, American National Standards Institute/ American Society for Non-Destructive Testing Standard AISI/ASNT CP-189, Qualification and Certification of Nondestructive Testing Personnel, published in 2001, or International Standard ISO 9712:2005, Non‑Destructive Testing - Qualification and Certification of Personnel, published in 2005. Any imperfection giving a response greater than that produced by a notch equal to 5% of the minimum design wall thickness is rejected;

(q) the Transport Canada mark and the specification designation marked on each cylinder is: "TC-SU 7726" followed by the service pressure expressed in bar;

(r) in addition to the requirements of clause 4.14 of CSA B339-08, the following tests are required to qualify a new design:

(i) a flattening test is performed in accordance with Clause 4.11 of CSA B339‑08, on three cylinders of each new design. Flattening to 8 times the wall thickness without cracking is required,

(ii) two pre-flawed cylinders are cycle tested in accordance with Clause 4.14.4 of CSA-B339-08, except that the cycling frequency does not exceed 5 cycles per minute. The flaw is machined longitudinally in the sidewall at approximately the mid- length of the cylindrical part of the cylinder in accordance with subclause of International Standard ISO 9809-2, Gas cylinders - Refillable seamless steel gas cylinders - Design, construction and testing, Part 2: Quenched and tempered steel cylinders with tensile strength greater than or equal to 1100 MPa, published in 2000. The cylinder shall have passed the test if the number of cycles attained without failure exceeds 3500 as a mean value of the two cylinders tested but with an absolute minimum of 3000.

Equivalency Certificate

SU 7726 (Ren. 3)



(s) the requalification period for the cylinders is five years;

(t) the Transport Dangerous Goods Directorate is advised prior to the cylinders being returned to service, where cylinders are requalified after having been subjected to fire;

(u) the documents referred to in Clause 4.19 of CSA B339-08, are retained by the manufacturer and by the Independent inspector, as defined in that standard, for the service life of the cylinder; and

(v) the certificate holder reports any incident involving loss of contents or failure of the cylinders to the Director, Regulatory Affairs Branch, Transport Dangerous Goods Directorate, Transport Canada.

This Equivalency Certificate serves as the registration of Norris Cylinder Company, pursuant to Clause 25.2 of CSA B339-08, to manufacture cylinders of the designs specified herein. Norris Cylinder Company's registered mark pursuant to CSA B339-08, is,

"M-0714" or "Image in permit";

Note: The issuance of this Equivalency Certificate in no way reduces the certificate holder's responsibility to comply with any other requirements of the Transportation of Dangerous Goods Regulations, the Technical Instructions for the Safe Transportation of Dangerous Goods by Air, the International Maritime Dangerous Goods Code, and the Canadian Aviation Regulationsnot specifically addressed in this certificate.

Signature of Issuing Authority


David Lamarche P. Eng., ing.


Permits and Approvals Division

Equivalency Certificate

SU 7726 (Ren. 3)

(The following is for information purposes only and is not part of the certificate.)

Contact Person: Larry Iltis

New Products & Compliance Engineer

Norris Cylinder Company

4818 West Loop 281

Longview TX 75603


Telephone: 903-237-7607

Facsimile: 903-753-3012


Explanatory Note

This Certificate authorizes the manufacture and use of cylinders based on the TC‑3AAM specification of CSA Standard B339-08. The applicant has demonstrated that by augmenting testing at manufacture, restricting certain design parameters as well as the types of gases that are to be contained, a cylinder with reduced wall thickness may be used with equivalent safety. Cylinders similar in design to the ones specified herein have previously been manufactured under a permit granted under the Regulations for the Transportation of Dangerous Commodities by Rail.

Legend for Certificate Number

SH - Road, SR - Rail, SA - Air, SM - Marine

SU - More than one Mode of Transport

Ren. - Renewal

Equivalency Certificate

SU 7726 (Ren. 3)

Appendix A


Steel cylinder chemical composition

(condition (e))



Product Analysis Tolerances

Element Mass Percent Under Minimum Over Maximum

Carbon 0.32 to 0.36 0.01 0.02

Manganese 0.70 to 0.90 0.03 0.03

Phosphorus 0.015 max. - 0.01

Sulphur 0.010 max. - 0.00

Silicon 0.15 to 0.35 0.02 0.03

Chromium 0.85 to 1.15 0.03 0.03

Molybdenum 0.15 to 0.25 0.01 0.01

Nickel 0.20 max. - 0.00

Vanadium 0.02 max. - 0.00

Copper 0.25 max. - 0.00

Tin 0.025 max. - 0.00

Equivalency Certificate

SU 7726 (Ren. 3)


Under Canadian Law, a foreign manufacturer of non-specification cylinders cannot be charged with an offence under the Transportation of Dangerous Goods Act, 1992 for failure to comply with the conditions of an Equivalency Certificate granted to him. However, certain remedies under the Act are available to Transport Canada in this eventuality.

These include:

1. detention of dangerous goods and consequently the means of containment containing them (subsection 17(1));

2. detention of the means of containment whether full or empty

(subsection 17(1));

3. directions not to import the means of containment or to return them to origin (subsection 17(3));

4. inspectors directions (section 19);

5. directions to importers of the means of containment to issue notices of defective construction or recall (subsection 9(2)); and

6. revocation of the certificate, thereby making any use of the means of containment an offence (subsection 31(6)).

If none of the foregoing are adequate, Protective Directions may be issued to prohibit or control the use of the means of containment (section 32).

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