If you’re going to eat Traditional East Indian food in North Vancouver locals would tell you Palki is the spot. However all was not well in the kitchen, ventilation issues for years caused the employees discomfort. Further to this we found many NFPA-96 fire hazards that required attention. The owner took corrective action and retained Evolve Mechanical Solutions to review the ventilation issues and come up with a solution.
The first immediate issue we noticed was the lack of make-up air. Actually there was NO make-up air at all! Make-up air is needed to replace the exhaust air through the kitchen hood. If you don’t you can have many ventilation and building envelope issues. Such as poor capture & containment, drafts, doors difficult to open, odours and heat lingering, etc.
What the owner did (see picture below) was to add a portable cooling unit and prop open the kitchen door. This really is a patch work solution that doesn’t solve the problem and just ends up disturbing the customers.
The second problem was that the existing grease duct size was 14″x8″. The bare minimum size for this length of hood and style of cooking required a 22″x12″ grease duct. It’s like trying to suck a water melon through a straw…. impossible. Some inexperienced engineers would simply increase the horsepower of the kitchen exhaust fan to get the required cfm. However NFPA-96 mandates that the velocity within the grease duct can not exceed 1800 fpm due to grease build-up and potential fire.
The third problem was the grease duct proximity to combustible material i.e. the wood in the walls. NFPA-96 states you must maintain 18″ clearance from wood to grease duct and 3″ clearance from dry-wall (limited combustibles). Since this was impossible to achieve 18″ clear we installed a clearance reduction system: 22 gauge sheet metal with 1″ insulation. This allowed are grease duct to be within 3″ to combustibles.
The forth major problem was that the existing grease duct penetrated a fire rated wall and exit corridor. This could allow for the spread of a fire from the kitchen to exit corridor easily. The BCBC 2012 requires that any penetration of a rated wall, ceiling, floor to be protected such that the wall, etc, maintains the original fire rating.
In this case we could either enclose the grease duct in a fire rated shaft or wrap the grease duct in a listed fire wrap. We chose the fire wrap for the ease of installation.
Finally the last issue, the existing fire rated shaft in the parkade had multiple penetration through it. This isn’t acceptable as it degrades the rating of the shaft thus allowing for fire to pass through it more easily.
Further to this the access panels on the shaft (to access the grease duct access panels) weren’t rated, again same issue above. It’s a weak point in the shaft that a fire could exploit.
Evolve mechanical solutions addressed the issues and added the required make-up air, increased the kitchen exhaust fan capacity and grease duct size accordingly.
Employees and patrons are now happier for it: