FAQs – Fitting

1.Q1. A pressure piping system design requires that two or more fittings be welded to one another in the piping. For example, an NPS ½ Thredolet® is to be welded to an NPS 8 ASME B16.9 butt-welding tee opposite the branch to act as a drain. Must the piping fabricator register the combination of fittings as a modified fitting?

1.R1. The welding of two or more fittings together, such as in the example given, is considered to be part of piping fabrication rather than modification of a fitting. Registration of the design consisting of the two or more fittings welded together is not required. Note, however, that the piping design engineer must have determined that the pressure-temperature rating of the combined fittings is still adequate for the rating of the line in which the combination fitting is installed. Combining fittings can significantly weaken one of the fittings because of the hole cut in it.

1.Q2. For the situation described in Q1, must the piping fabricator have modification of fittings in its registered quality management system?

1.R2. The piping fabricator need not have modification of fittings in its registered quality management system in order to be able to combine fittings in accordance with the engineered design when fabricating a pressure piping system.

1.Q3. Do two butt weld fitting pipe tees which have been split on the horizontal axis, with the two parted branch sections welded together with a full penetration weld to form a cross, require CRN registration for this modification?

1.R3 Yes. The original Canadian Registration Number (CRN) assigned to each tee would no longer cover the design of the altered fitting. It is understood that the original manufacturer’s markings and warranty of the tee would no longer be applicable to these fittings once fabricated into a cross.

2.Q1. A new pressure piping system with an internal volume exceeding 500 L is to be installed. Is it required to use registered fittings in such a pressure piping system?

2.R1. Yes, registered fittings are required in an unregistered pressure piping system. Section 14(6)(a) of thePressure Equipment Safety Regulation (PESR) is an exemption from design registration only. All other applicable requirements of the PESR and the Pressure Welders Regulation apply.

3.Q1. Is pipe required to have a fitting CRN?

3.R1. No. Pipe is material as plate is material. Piping, on the other hand, is an assembly of pipe and fittings. Piping must be registered as a pressure piping system unless registration of the size or type of pressure piping system is exempted by the Safety Codes Act or regulations.

4.Q1. If a nozzle is welded to an ASME B16.5 blind flange, does the blind flange retain its B16.5 pressure-temperature rating? The nozzle is attached at the centre of the blind flange and the attachment weld is a full penetration weld through the nozzle neck plus an appropriately sized fillet weld. For the purposes of this question, it is assumed that the nozzle neck and any flange at the other end of the nozzle are of equal or higher rating compared to the blind flange.

4.R1. If the attached nozzle’s fully corroded inside diameter is smaller than the outside diameter of the smallest size (NPS) of reducing outlet requiring a hubbed flange listed in column 2, 4, or 6 of Table 6 of ASME B16.5-2003, a standard blind flange may be used at its B16.5 pressure-temperature rating. Larger diameter nozzles would require the use of a hubbed blind flange (refer to the Notes to Table 6 for details of the required hub size) to allow the full ASME rating of the blind flange. Otherwise, the maximum allowable working pressure of the blind flange with the central hole must be calculated in accordance with the applicable code of construction and for the required maximum temperature.
Note that this is a variation of the B16.5 Table 6 requirements to cover the situation where the nozzle is set onto the blind flange.

5.Q1. A bleed ring or spacer is manufactured from plate or a forging. This ring will be gasketed between two flanges. A bleed ring would be thick enough to allow a small tapped hole, to which a valve may be attached so that some of the contents of the piping may be bled off. Does this bleed ring or spacer require a CRN?

5.R1. No. Such bleed rings or spacers would be comparable to very thick, solid metal gaskets and gaskets are not registered as fittings although they are pressure components. A valve attached to a bleed ring would have to be a registered fitting. Note that some end users may require such components to be registered as fittings before they may be installed in that user’s facility.

5.Q2. Do bleed rings require registration?

5.R2. No, provided that the ring material and finish of contact faces shall conform to the requirements of ASME B16.5; the pressure tap design complies with ASME B16.36 requirements for threads, tolerances, and diameter (corresponding to thickness); the outer diameter and bore of the ring comply with B16.48 paddle dimensions; and the ring is sandwiched between flanges.
Flanged piping sections (piping “pups”) consisting of two flanged ends with a short pipe (or no pipe) between shall not be considered a bleed ring. These items will require registration.

7.Q1 Do Heat Exchanger plugs need to be registered with a fitting CRN prior to its use?

7.R1 Yes, fabricated mechanical plugs that are threaded into or are expanded within a tube will require a fitting registration. These fabricated plugs typically are made from multiple material specifications that form a pressure component. The complex shape, variable materials, and sealing mechanism give rise to safety concerns over tube or tubesheet damage and the design of these plugs will require a submission to ABSA Design Survey for registration.

However, solid taper plugs which are physically hammered into place do not require registration because they are material only, and materials do not require registration. The solid taper plugs will require compliance with the vessel code of construction for material specifications and traceability.