By Norm Grusnick, P. Eng
We are entering a period of significant change when it comes to energy code upgrades and more stringent mechanical engineering specifications. The engineers who take the time to understand the significance and implications these changes are having on our industry will do well. Others? Not so much.
The BC Building Code (BCBC) currently cites ASHRAE 90.1-2010, and that standard includes increased minimum pipe insulation thicknesses (size) over previous editions of 90.1. The National Energy Code for Buildings-2015 (NECB-2015) is also an improvement over previous editions, particularly when it comes to minimum mechanical insulation thicknesses.
The tables relating to minimum pipe insulation thicknesses in NECB-2015 were based on ASHRAE 90.1-2010 with a few changes reflecting the Canadian experience. However, NECB-2015 goes beyond ASHRAE 90.1-2010 in a very significant way. But before we get to that, let’s take a very brief look at “code harmonization”.
The federal government entered discussions with those provinces that currently have their own building/energy codes, namely BC and Ontario. The ultimate goal is to take the most stringent requirements from the provincial codes and the federal codes in order to ultimately establish a uniform code throughout Canada. This is ongoing with no end date at this time.
A number of mechanical engineers have revised their specifications to reflect the changes in NECB-2015. Keep in mind these codes require minimum. An engineer or a municipality, such as the City of Vancouver, can, if they wish, go “better than code”—that is, above minimum. This is where NECB-2015 comes into play. Because of statements in that code, yes, size (thickness) does matter. The following is copied directly from the sections on duct and pipe insulation:
5.2.2.5. Duct and Plenum Insulation
5.2.2.5.2) The insulation thickness used to determine compliance with Table 5.2.2.5 shall be the thickness of the insulation after installation.
5.2.2.5.8) Manufactured thickness shall not be altered.
5.2.5.3. Piping Insulation
5.2.5.3.8) The insulation thickness used to determine compliance with Table 5.2.5.3 shall be the thickness of the insulation after installation.
Table 5.2.5.3. This specifies insulation with upwards of 50% greater thicknesses than the previous NECB.
We should be aware there are no exceptions when it comes to insulation coverage. Either insulation is not required (per ASHRAE 90.1-2010 or NECB-2015) or it is. If insulation is not a requirement, this is the express decision of the “authority having jurisdiction”. Insulation must therefore be continuous throughout the pipe system, over valves, elbows, etc., to the same R-value as on the adjacent piping. The same applies to insulation on below ambient pipe systems where the vapour barrier must also be continuous. In practical terms, this is often difficult to achieve.
NOTE: Plastic pipe (e.g.) PEX is not treated any differently in the codes than metallic piping. If metallic piping has to be insulated, then so must plastic pipe.
Engineers and mechanical contractors must be made aware that clearance between components is critical, that saddles and hangers must be correctly sized, and that ball valves must come with valve stem extensions.
It is incumbent on us to educate ourselves and all involved parties. Projects including the BCICA QAC program have a third-party inspection service to make sure these new specified thicknesses are installed as specified. ■