Unvented Heaters

 The story behind the Ontario Fuel Safety Program Advisory

Have you gotten a notice about unvented heaters in your poultry barns and wondered what it meant?

Dan Ward is an Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) engineer out of the Stratford, Ont. office. Because of what he called a “random” inspection at a job site, Ward says flags were raised about how the unvented heating systems were being operated in barns.

The Technical Standards and Safety Authority (TSSA) is a private company delegated by the province of Ontario to enforce Natural Gas and Propane Installation Code. One day in 2011 a TSSA inspector happened to drop by a jobsite for an impromptu visit but was allowed look around a turkey barn under construction where unvented gas heating equipment was being installed.  A few deficiencies with the equipment and the installation were identified that needed to be addressed to bring them into compliance with Gas Code or the inspector could shut off the gas to
the barn.

The farmer was irate, said Ward. He had birds coming in; there were timelines, but four months later he was still trying to negotiate a solution. What’s wrong with my heaters, he was asking? He had three types of unvented heaters in his various barns and these were the same type of heaters commonly used in the Ontario poultry industry, so why were they not good enough now?

It turns out his question opened a can of worms.

But first, a bit of background: the Natural Gas and Propane Installation Code CSA-B149.1 is the technical document describing requirements for the safe installation and operation of gas appliances. It’s a national document that is adapted by each province and addresses details like the separation distance between a heating appliance and combustibles, the venting of the products of combustion, gas shutoffs, etc. Only approved appliances – those bearing the required certification sticker from the Canadian Standards Authority (CSA) or Underwriter Laboratories of Canada  (ULC) – may be installed under the Gas Code.  

The code also states that unvented infrared heaters shall be provided with mechanical ventilation to remove the products of combustion outdoors, primarily CO2 and water vapour, with a ventilation volume of at least 300 cfm per 100,000 Btuh of heater capacity. The ventilation system also needs to be interlocked with the heater(s) so that the heater(s) automatically shuts off or won’t start unless the fan is running.

Where it is not possible to interlock heaters, section 7.22.2 describes the use of a carbon dioxide detector equipped with an audible and visual alarm. While Ward says this is possible, in his experience it is neither common nor necessarily reliable inside the challenging barn environment.  

When located in a large and adequately ventilated space, section 8.24.5 states that an appliance may be operated by discharging the combustion products directly into the space, subject to the approval of the authority having jurisdiction (this is the TSSA in Ontario) and provided the maximum input of the appliance does not exceed 20 Btuh/cubic foot of the space in which the appliance is located. This clause attempts to put an upper limit of the size of the heater for the space.

There are three types of unvented heating appliances commonly used in poultry barns and none are interlocked with the ventilation system as per the code requirements. The unvented infrared brooder heater does not vent outdoors and is common in poultry barns. The direct-fired box heater, common in both poultry and swine barns, draws air for combustion from either inside or outside the building and discharges all products of combustion into the barn. The stationary infrared tube heater pulls air for combustion from outdoors and could be vented outside but many are not.

The 2011 site visit incident uncovered several unvented heater infractions. The first problem was that there was no mandatory interlock between heaters and ventilation fans. The second issue was that the minimum ventilation rate would not be met during the initial brooding period due to ventilation settings. Some of the heaters were also missing the proper certification stickers.

A meeting was held with the TSSA to discuss a number of possible solutions to the unvented heater issue for this farmer and the agriculture industry as a whole since it was estimated there could be up to 2,000 barns with this type of equipment in Ontario, mostly for poultry and swine.

The first solution to be brought forward was to vent all heaters outside the barn, which would work for radiant tube heaters but not the box heater or pancake-style brooder heaters, which meant that these would have to be replaced.

A second solution would be to continue to use unvented heaters but that would require each farm to undertake a costly paperwork process to apply for a variance from the TSSA.

A third solution was to actually seek changes to the Gas Code for unvented heaters in livestock and poultry barns. Similar exemptions have been made for the greenhouse industry in the past to allow the use of carbon dioxide generators inside these structures with specific operating requirements.

The focus was on the third solution – an amendment to specifically address the use of unvented heaters inside livestock and poultry barns. Ward says that five commodity groups (Chicken Farmers of Ontario, Egg Farmers of Ontario, Ontario Broiler Hatching Egg & Chick Commission, Ontario Pork and Turkey Farmers of Ontario) came together to hire David Stainrod, a private Gas Code expert, to draft a Gas Code amendment. This document was presented in May 2014 to the Ontario technical committee for review and then taken to the National Gas Code Review committee meeting in Calgary in June 2014.

The amendment was well received at the Ontario technical group, where most discussions are usually around residential applications of the Gas Code, not agricultural. But nationally, the support wasn’t there for the adoption of the amendment. “It put us in a bit of a lurch,” said Ward. On the provincial level though the TSSA was in agreement, they proposed to add the amendment to the Code Adoption Document each province uses to implement the latest version of the National Gas Code.

On Aug. 25, 2014 the TSSA issued a Fuel Safety Program Advisory (FS-212-14) that outlines specific requirements for the use of unvented natural gas or propane heaters in livestock and poultry barns. The requirements came into effect for new heater installations as of Oct. 1, 2014; existing barns have until Jan. 1, 2016 to comply with the new requirements. This is a notice that farmers would likely have received from their commodity boards, said Ward.

If you have an unvented heater, TSSA basically wants third party verification by a licensed Ontario engineer to sign off on barn ventilation system design. Two calculations are required to be posted in a prominent place at the entrance to each barn:

1. Minimum ventilation rate of the barn (mechanical or natural ventilation) when the heaters are operating is not less than 300 CFM/100,000 BTUH (0.003 CFM/BTUH) of heaters input (clause 7.36.1c)
2. Maximum input of the heating appliances does not exceed 20 BTUH/ft3 of the space in which the appliance is located (clause 7.36.1d)

These calculations will continue to be valid as long as no equipment changes are made to the ventilation system, said Ward, and will affect any barn with unvented heaters.

If farmer hires an engineer to verify the ventilation system as per amendment 7.36.1 for an unvented heater then the farmer is exempt from the requirement of having the mandatory interlock.

The TSSA does have the authority to enter private property to inspect if a safety issue with the gas equipment is suspected, but it is more likely that farmers will be asked by a licensed gas mechanic who may be installing or servicing gas equipment or the fuel supplier to provide the signed calculation sheet for each barn.

The specified ventilation rates are not hard to meet, said Ward, since the minimum ventilation rates to control humidity levels is usually higher than the above rate. The exception maybe in the first day or two of brooding in broiler or turkey barns but this can be addressed by increasing the ventilation rates.

Your other options are to vent your heaters outside if you are using radiant tube style heaters, or hook up a CO2 sensor to your ventilation system.

And what about the farmer at the core of all of this? He was granted a two-year variance to continue operating his barns, said Ward, while an industry solution was developed. He now has the same options as everybody else if he wants to continue to use unvented heaters in his existing barns after Jan.1, 2016.