Sunridge Mall in Calgary – Custom Case Study
VGF has designed and installed many custom projects over the years, indoor, outdoor, large, and small. Here you’ll find a collection a few favourite projects, some straight-forward, some filled with challenges, and others that are just plain ‘ole fun. We put them together to form the Vancouver Gas Fireplaces Custom Case Studies.
The challenge for many commercial fireplace installations is balancing the combustion and dilution air with the vent system. This was certainly the case when Vancouver Gas Fireplaces was designing the air and venting system for the Sunridge Mall in Calgary.
Many commercial buildings have fairly strong negative pressure. In other words, fireplaces would have a difficult time venting if not helped by mechanical means. This situation is exacerbated in many installations by the fact that the venting for the fireplaces often has a number of twists and turns before getting to an outside location.
To counter potential venting problems, Vancouver Gas Fireplaces designs most installations as closed balanced systems. To create a closed balanced system, our aim is always to ensure that most of the air required for primary and secondary combustion, as well as the dilution air need for venting, is brought directly into the fireplace base, then fed up into the fireplace. To determine the amount of air required to be delivered to the fireplace requires calculations based upon the BTU’s of the burner, the volume run by the fireplace enclosure and vent pipe, and a bit of intuitive conjecture based upon experience.
In most cases of commercial installation the balancing of the fireplaces is made easier by the installation of fixed glass as a safety barrier. This is often complicated by the addition of a second layer of glass with an air space between it and the first layer. These are in place to protect against potentially hot glass. Provisions must be made for bringing air into the base of the fireplace and up between the two layers of glass for a cooling air wash.
Additional challenges were presented when Vancouver Gas Fireplaces was designing the air and venting system for the Sunridge Mall in Calgary. The fireplace was to be viewed from four sides with little support structure and we had to power in the make-up air from the roof. It was decided that we would bring the air down into the base of the fireplace by means of the four hollow support posts. They would have internal stops built into them slightly above vent attaching boots at the intake, and slightly below vent attaching boots for the delivery into the base.
The initial vent run for the make-up air was single intake, powered by an inline fan just below the roof. Just underneath the intake fan, the vent was split into two runs, each with a motion activated inline heater so that the air was heated up before reaching the fireplace, increasing the efficiency of the combustion. From the two vent runs, the system was split again to enable the air to move down the four support posts. In the base of the fireplace a plenum was designed to distribute the air both into the burner for the combustion and dilution requirements, and between the glass layers for a cooling air wash. Dampers were set into the throats of the various delivery runs so that the system could be effectively balanced.
Static pressure, which is essentially the friction resistance measurement in moving air through ducts, was a challenge for this project given the convoluted duct delivery system. The system had to be broken into its parts, tested and added together then balanced by means of speed controls on both the intake and venting fans, as well as the dampers.
In the end the fireplace operated as it was intended providing an attractive feature and gathering spot for the mall. For us the visual of the fireplace and its design were just the tip of the iceberg. Working out the air system and the mechanics to control it gave us a unique opportunity to expand our knowledge of customized fireplace design.
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independent preliminary review by the Equipment Approvals Manager of the Gas Safety Authority of British Columbia and a subsequent field review and inspection by Independent Arms Length Government Inspectors.