A year ago, I wrote an article about plastic venting materials and the probability of significant changes being introduced in the B149 gas code to bring about some standardization to the use of these materials for venting natural gas and propane appliances. Where are we now, and how are the changes being implemented? When researching this article, the word chaos kept popping into my head. I want to give the various code officials and the inter-provincial gas advisory council top marks for dealing with such a widespread and fundamental change; however much remains to be done before sanity returns to the plastic venting world. I am not aware of a major change like this ever being implemented so quickly, and there are many unanswered questions, dissatisfied stakeholders, and confused contractors, manufacturers and suppliers. Lets go back to how we got into this mess in the first place. When writing my article a year ago, I came upon a curious thing. The M86 version of the B149 (the version in force when many appliance manufacturers started specifying off-the-shelf ABS and PVC plastic for venting) clearly stated that these venting systems (plastic venting systems were classified as BH) be consisting entirely of factory made parts and, in clause 5.10.3, that (a) a type BH venting system complying with the ULC S636 Standard for Type BH Gas Venting Systems, or (b) a venting system certified as a component of the appliance and provided by the manufacturer. I referenced this in my previous article and my good friend Barry Bowman (Bowman Mechanical/HRAI SkillTech) wrote me shortly after the article appeared and pointed out, correctly, that the then current version of the code allowed the use of materials specified by the appliance manufacturer in other words you could go to your local supplier and pick up generic ABS pipe fittings and solvent cement and have at it. A pretty significant change, no? I think it would be a useful exercise for someone knowledgeable in the evolution of the B149 to do some backtracking and find out just how the plastic venting rules changed so fundamentally.
Industry resistance
So now we have a situation where most jurisdictions in Canada require S636 certification of all plastic venting systems, both in new construction AND in the replacement of existing appliances. There is huge push-back in some sectors of the industry. The most notable objectors (and for good reason) are the water heater renters of Southern Ontario who face potentially crippling economic consequences should they be required to rip out and replace old venting systems. Many of these old venting systems will not go silently into the dark recycling bin. Some of them may be nigh impossible to replace without major structural disruption of the building they are installed in and, although I can appreciate their concern for the health of their businesses, I firmly side with the code officials in all of this, who are most concerned with the health of the citizens in their jurisdictions. This goes to the heart of the issue and the state of things today regarding plastic venting. Not enough research has been done. Plastic venting systems were installed in many buildings throughout the land, in a manner that makes them impossible to replace in many cases. This was done for many years even though proper aging studies were never done to see how long this stuff would last. Why would you install a major building component like a venting system with no reasonable way to replace it and no assurance that it would last the life of the structure? This is a hard question that HAS to be asked.
Jumping through hoops
Timing for the introduction of the new/old rules have varied by province, but by the time you read this it is my understanding that all jurisdictions will have implemented them. I have been told there will be a high level of scrutiny by code officials in every jurisdiction. Some variances will be granted. It is important that you check with your local code officials to see how you might be affected. Some variances and exceptions I have heard of include:
Allowance to use existing venting in replacement jobs where replacement is difficult or impossible. In most cases, pressure testing and examination of the existing vent is required and new S636 material has to be provided for the initial (3 to 5 feet) connection to the appliance. Application for this variance must be made on a job-by-job basis and fees will apply in many areas. The details I read from Technical Standards and Safety Authority (TSSA) in Ontario made perfect sense, but make it very expensive and time consuming to re-use an existing plastic vent. I dont anticipate too many people jumping through those particular hoops. Allowance to use non-certified fittings where special fittings are required to connect to the appliance and certified fittings are not yet available. There is a deadline of July 1 2008 for appliance manufacturers to get their transition fittings certified. Allowance for use of non-certified concentric vent kits and condensate drain tees for a limited time period, to be determined as certified material becomes available.
On the job site
Strange things have been happening during the transition to the new rules. Here are some interesting examples:
I have heard that some local inspectors have stated that they will require appliance air intake ducting to be of the same material as the venting. This makes no sense at all to me. The only explanation I have heard is that it will prevent installers from mixing up venting and air intake materials. A highly unlikely, and easily identified and corrected error. Manufacturers of certified product refuse to allow any mixing and matching. You must use their pipe, their fittings and their solvents or the venting system is not certified and they will not warrant it a major headache for all concerned. I read a draft document from one province that stated approved primer must be used as directed by manufacturers instructions for all applications before cementing plastic venting material & fittings regardless of ambient temperature. One manufacturers instructions however clearly state that if ambient temperature is above 0?C joints can be assembled without primer. If in doubt, go with the code officials interpretation, I have always been told. Some appliance manufacturers just arent getting it. I have heard reactions like - Nobody has the right to tell me what kind of pipe to use on my boiler! and If you set the controlling aquastat to 65?C you can use PVC . On the temperature rating front, there are many strange issues. Some appliance manufacturers state that PVC material approved for a maximum flue gas temperature of 65?C can be used on their appliance even though it is clear that the appliance flue temperature can and will at times exceed 65?C by a large margin. Appliance manufacturers are asking (rightly so), can we transition from CPVC to PVC at some point if we can prove that the flue temperature will drop under the 65?F upper limit? Good question.
I could go on and on, and I would be interested to hear any strange stories our readers might have. If you have a good one, drop me a line. This whole thing has been a bit of a Gong-Show but, at the end of all of this, I am sure we will work through the problems and the consumer will benefit from safer, longer lasting gas venting systems. In no way do I think this will be the last time we revisit this matter though. I have a sneaking suspicion that as new materials are developed and new problems arise, PVC and CPVC will fall out of favour and different systems will become popular. Hopefully as this happens we will have a much longer period of time in which to test, certify and implement new venting systems.
Roy Collver operates Mechanical Systems 2000 in Calgary. He can be reached at royc@ms-2000.com.