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SECTION IV

Subject Interpretation File No.

Acceptable Coupling Use Under Section IV Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-04-07 BC04-168

HG-301.2, Tube Thickness Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-04-08 BC04-1222

HG-701.1, Mounting Safety and Safety Relief Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-04-09 BC04-1222

Introduction/Preamble and Scope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-04-11 BC05-537

Use of Hot Water Supply Boilers as Water Heaters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-04-06 BC04-1365

Table HF-300.1 [Note (19)] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-04-10 BC04-1366

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Interpretation: IV-04-06

Subject: Use of Hot Water Supply Boilers as Water Heaters

Date Issued: January 14, 2005File: BC04-1365

Question (1): Does the term hot water supply boiler as used in Section IV mean that it is a potable

water heater?

Reply (1): No.

Question (2): May an H stamp boiler be installed as a commercial potable water heater?

Reply (2): This is beyond the scope of Section IV.

Question (3): Does Section IV prohibit an H stamp boiler from having direct contact with potable

water?

Reply (3): No.

Interpretation: IV-04-07

Subject: Acceptable Coupling Use Under Section IV Construction

Date Issued: January 28, 2005

File: BC04-168

Question: Does Section IV prohibit the use of mechanical pipe couplings with elastomeric seals in the

construction of heating boilers?

Reply: No, provided the couplings meet the requirements of HF-203.

Interpretation: IV-04-08

Subject: HG-301.2, Tube Thickness Requirements

Date Issued: January 28, 2005

File: BC04-1222

Question: Is it permissible to use tubes with a minimum wall thickness that meets requirements per

HG-301.1, with additional wall thickness on the tube ends that meet the added 0.04 in. thickness required

by HG-301.2, for rolled tubes provided all engagement with the tubesheet or head occurs within the boundaryof the thicker portion of the tube ends?

Reply: Yes.

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Interpretation: IV-04-09

Subject: HG-701.1, Mounting Safety and Safety Relief Valves

Date Issued: January 28, 2005File: BC04-1222

Question: Must the safety/safety relief valve(s) be mounted on the outlet piping of a coil or header type

boiler?

Reply: No, the safety/safety relief valve(s) may be mounted either on the outlet piping or outlet end of

a coil or header type boiler.

Interpretation: IV-04-10

Subject: Table HF-300.1 [Note (19)]

Date Issued: April 15, 2005

File: BC04-1366

Question: Section II, Parts A and D reference the 1992 Edition of SA/CSA-G40.21 that year date of the

specification lists metric grades 260W and 300W and does not contain equivalent imperial unit grades 38W

and 44W that were listed in the prior and subsequent editions of CSA-G40.21. Section IV, Table HF-300.1

[Note (19)] lists SA/CSA-G40.21, grades 38W and 44W as acceptable substitutes for SA-36/SA-36M in

Section IV Construction. Is it permitted for metric grades 260W and 300W, as listed in the 1992 Edition

of CSA-G40.21, be used in lieu of SA-36/SA-36M for Section IV Construction?

Reply: Yes.

Interpretation: IV-04-11

Subject: Introduction/Preamble and Scope

Date Issued: June 15, 2005

File: BC05-537

Question: Can a boiler be designed and stamped per Section IV when heated/fired with reciprocating or

turbine engine exhaust gas only?

Reply: Yes, provided all requirements of Section IV are met.