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Vent In Roof

06/23/2016 12:10 AM

We have a machine that generates a large amount of heat and we plan to vent this heat through the roof

This is a commercial building with a metal flat roof. We plan on purchasing a 12 inch roof vent cutting a 12 inch hole in the roof. Then install commercial roof vent that we are going to purchase. The location is 25 feet from the side of the building.

Our Health and Safety representative thinks that we are going to need a "engineering letter" to be able to cut this small hole.

I have no problem hiring a engineer if in fact its a requirement. I can find any code requirement other than protecting the hole while under construction.

I called a local engineering company and they thought my request was unique as they had not had such a request in the past.

We are located in Ontario Canada

Any comments would be appreciates on the forms opinions

Thanking you in advance

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#1

Re: Vent In Roof

06/23/2016 12:27 AM

Do you need an "engineering letter" to take a dump? Bureaucrats can engineer the crap out of anything. Of course, if your laws allow that, then there may be no hope.

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#2

Re: Vent In Roof

06/23/2016 12:53 AM

Can your Health and Safety representative produce any statutory evidence that such a document is needed? And why? And what would happen if you, after the fact, were found out?

He could have a touch of hysterical CYA disease.

I'm not in Canada and know nothing about their building codes.

If you are ONLY venting air and no pollutants, cut the hole and be done with it.

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#6
In reply to #2

Re: Vent In Roof

06/23/2016 6:58 AM

Lyn is spot-on - GA there. Sometimes the H&S staff are overzealous. If the attitude is "when in doubt, overdo it", I react with "when in doubt, find out and confirm". I'm not familiar with your laws, but usually engineering input would only be required if you are affecting the roof's structure. So if you have a steel framed roof with galvanised cladding, and you're cutting a hole in the cladding only, it should be OK. But then, not all laws are governed by common sense... There are any aerodynamic issues to consider, I'm not a roofing or building specialist.

I've had some success with installing turbine ventilators (Whirlybirds?) to extract machine-generated heat, but, ahem, be careful about installing them above electrical panels. One was damaged by vandals throwing stones, causing it to stop turning. and trust me, water can then enter!

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#7
In reply to #2

Re: Vent In Roof

06/23/2016 7:33 AM

Exactly, Its good that the HS rep brings it up, but what does he know about structurly. If its Spancrete structure, yes. if its a pre-engineered steel building, and your only cutting through insulation and the steel roofing, no structural component's like perlins and the like., Than can fall on your subcontractor doing the job.

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#17
In reply to #2

Re: Vent In Roof

06/24/2016 9:36 AM

I can tell you are not in Ontario, Canada. The hoops we have to jump through to run a business here are gaining in number all the time. In theory, even if your only ventilation is opening windows in an industrial plant, you are subject to Ministry of Environment review, not only to what substance(s) are being expelled, and yes,,, air is a substance, but how much noise is emitted as well.

You are correct that OHSA-that is ours- is likely not required to be involved, except,,,, that putting a hole in the roof now makes it a construction site which is subject to a whole lot of other rules which to which OHSA does apply.

Just saying that different jurisdictions have different rules.

But, I do agree with you about CYA. It may be the only way not to get prosecuted.

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#19
In reply to #17

Re: Vent In Roof

06/24/2016 2:14 PM

No, I am not.

I realize that common sense may have no place in dealings with any government.

The chlorine example is true even here, in another context. MANY household cleaners/chemicals may be considered hazardous materials if brought into the workplace.

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#20
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Re: Vent In Roof

06/27/2016 8:02 AM

Absolutely true. If I purchase said "cleaners/chemicals" for the work place,I am required to have an MSDS on file. If I buy the for home, I don't need one. Sure makes a lot of nonsense, as most governmentally legislated items do.

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#21
In reply to #20

Re: Vent In Roof

06/27/2016 8:11 AM

Also a large file that well organized as well as easily accessible for the MSDS paperwork

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#22
In reply to #21

Re: Vent In Roof

06/27/2016 10:07 AM

Readily accessible to the workers, if not posted where the "hazardous" chems, are used.

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#23
In reply to #22

Re: Vent In Roof

06/27/2016 10:33 AM

Readily accessible to the workers,

that's what its there for. I should have made that clearer.

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#24
In reply to #17

Re: Vent In Roof

06/27/2016 11:48 AM

You would do well in NYC.

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#25
In reply to #24

Re: Vent In Roof

06/27/2016 12:00 PM

I did work for a company that used to do a lot of construction in NYC, but I wasn't involved in all the "legal/other" stuff, but I did hear a lot of stories. Unless you had some rather deep pockets (or were able to build the extra "costs" into your bid) you were pretty much prohibited from doing any construction there. I know of a few companies that found out the hard way.

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#3

Re: Vent In Roof

06/23/2016 1:46 AM

A 12" hole sounds awfully small for a proper exhaust fan.....I would think you also would need a roofer to install a proper roof curb to mount your exhaust fan on...This could require several different permits, well at least here in US, maybe the engineering letter would be some sort of sign off on your plans or design....What cfm are you targeting, and what is that based on?

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#4

Re: Vent In Roof

06/23/2016 2:52 AM

Hi, I bet with Lyn. When the building is occupied with people inside, the requirements on comfort zone is the primary concern of OSHA so with you as the facility or building owner.

Indoor comfort zone requirements can be looked under OSHA's mandate and as per ASHRAE standards.

My advice is, simulate the conditions inside the building's first using CFD AutodDesk is capable of analyzing the interior gas dynamics and temperature trend indoor with respect to how large your vent would be, if exhaust fan would be necessary and how much air inside should be replenished with fresh air or not.

Or, consult a team of expert, who can think fit to recover this heat for building application.

You might as well use open source Fire Simulation FDS if it's applicable. (I think it is)

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#5

Re: Vent In Roof

06/23/2016 4:01 AM

Mind you sharing what machine this is that produces the heat? Generally you might want to check the following:

1. ceased brake - fix it and no heat

2. Manufactures cooling requirements and options. Do you run a outdoor machine in a contained environment?

3. A roof vent might not be the preferred solution (see2.) Where will the fresh air (preferable cool air) come from.

4. Last but not least any installs on a flat roof should require a review by a structural engineer. Given you are in Canada you should have a roof engineered to snow and wind loads, but better make sure you get access to the building documentation and design specs. Nothing worse than the hole in the wrong spot or the roof vent come visit you next to your machine.

5. what else is in the building that might be impacted by your cooling attempt? If there is a lot of heat involved think about a water cooling process. see 2.

You do not need a letter for the hole but certainly need to think about the installation and the impact on the building and structure.

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#8

Re: Vent In Roof

06/23/2016 9:42 AM

I am in Ontario too.

What's an engineering letter? An engineered document requires a stamp to validate it. If you are cutting a non- structural (in the sense of loadbearing, such as purlins or beams) element of the roof I know of nothing in the building code that dictates that. What I do know though, is the MOE may require a Certificate of Approval (which will require an engineer) if you are going to be exhausting process air- technically they could even require for high point loads of heat.

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#9
In reply to #8

Re: Vent In Roof

06/23/2016 9:49 AM

A company where I worked we were going to put a penetration into a side wall that was Spancrete. did not know what effects this would have on the integrity, so I contacted the manufacturer Spancrete engineering department. Just a prudent move.

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#14
In reply to #8

Re: Vent In Roof

06/24/2016 8:27 AM

I would agree that unless the addition to the roof is adding substantial load it should not require an engineers review. Might want to check with the original building plans to see what was allowed for dead load and snow load on the roof. Any addition upwards on the roof will add some dead load in terms of snow load as the add on will create snow banks. The National Building Code or the Ontario Building Code will give you what the design load should be.

As far as the MOE is concerned, any time you make an alteration to existing exhaust system you have to, legally, get your emissions certificate updated. I've been through that even when I reduced my emissions and noise levels. Check to see what your emissions certificate has listed, or even if you have one. If you have to create or change, I have found it the most expedient to hire a consultant to do it for you. My application is about 1 1/4" thick with all the documentation. The contents of the application will depend on how much and what you are discharging or are planning on discharging.

If you have access you will have to look at the Environmental Protection Act R.S.O.1990 Section 20.2 of part II. If the exhaust hole has a fan in it, i.e. it is powered, you may have to have it extend 2 meters or more above the roof, and you may have to have your exhaust sampled to see what you are discharging, unless you have MSDS's on anything used that may be exhausted.

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#10

Re: Vent In Roof

06/23/2016 10:30 PM

Based on my Ontario experience if you are venting anything out of a building you need an air permit. At the time I was in the FRP molding business and we had to calculate the amount of styrene from that area also the paint booth need an Air Permit I was told by the ministry that even air with no known source of contaminants needed an air permit. That was in early 90's under a useless socialist government.

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#11
In reply to #10

Re: Vent In Roof

06/23/2016 11:19 PM

I'm not sure how you equate generation of styrene fumes and other by products of molding FRP and paint booth exhaust, filled with paint solvents, with exhausting the plant air breathed by the occupants of the building.

You're suggesting that buildings must be sealed? That means no evaporative coolers allowed?

That's ridiculous.

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#16
In reply to #11

Re: Vent In Roof

06/24/2016 9:32 AM

I am in full agreement with your comments, it was ridiculous and I have even more foolish government activities from that time of the Bob Rae government. Like the time an associate was walking his dog in Toronto and came upon a utility repair but there were 13 Ministry of Environment vehicles with 30+ men and women with white hats and clip boards milling about with ministry identification. He asked what happened and was told " toxic spill" water main broke, he replied that is drinking water! The answer was if it has chlorine in it then it is under our responsibility as a toxic substance. In another incident a road sander lost control and flipped on its side during a blizzard, police were called but told him the were not coming out since no injuries. They righted the truck towed it back to the yard and sent out a loader and another truck to clean up the sand & Salt. MOE (Ministry of Environment) arrived wanting to know what happened to the toxic spill and freaked out when told that it was being spread on the highway according to the road maintenance contract. He was threatened with charges for unauthorized disposal of toxic substance. I think you get the point of an over active environmental enforcement.

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#18
In reply to #16

Re: Vent In Roof

06/24/2016 9:39 AM

I think all of us here have similar stories.

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#12

Re: Vent In Roof

06/23/2016 11:33 PM

I too, know nothing about the Canadian codes, but then again no one who has commented knows anything about the size of the building, what materials are used/stored in it, nor the source/quantity/quality of the heat that you're trying to remove.

Granted a 12" fan isn't that large, but it is possible to pull anywhere from 800 to 3,000 cfm or more out of the space, no problem on 100x100x20 ft building, potential problem if it's 50x50x20ft, big problem if it's 25x25x10ft; namely where is the make up air going to come from?

You didn't say how your equipment gets hot, but if there's any combustion inside the building (water heater, heating system, oven, etc.), then the negative pressure created by the exhaust fan could easily upset the combustion process and draw carbon monoxide into the building, and don't forget your bathroom exhaust fans.

Then there's the fire codes to be concerned about, nothing worse than an exhaust fan that keeps sucking in fresh air during a fire because it doesn't have a high temperature cutout and shutters with a fusible link to stop the egress of flames to the roofing material.

I've been to Ontario in the winter, do you really want to increase your fuel bill because of the need to heat the make up air?

Hire an engineer and let him work with your insurance carrier to ensure a safe installation.

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#13

Re: Vent In Roof

06/24/2016 12:34 AM

"Our Health and Safety representative thinks that we are going to need a "engineering letter"..."?

The job of your Health and Safety representative?? is to explain to you WHY you need proper documentation!

You explained what you plan to do to alleviate the over heated area in the vicinity of the machinery, now the ball is in his court

Considering that his title includes the word "SAFETY" he should be familiar with all relevant codes and regulations.

He should also be cognizant of the environmental and fire regulations regulations that might require a discharge permit as well as sire shutters.

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#15

Re: Vent In Roof

06/24/2016 9:05 AM

I would have it reviewed by a structural engineer. Roof decking is structural. Typically, reinforcement angles are installed on 2 sides of the opening (maybe all 4)....rib orientation dependent.

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