Commercial Kitchen Appliance ETL Ratings

If you are designing a commercial kitchen, you need to find out which code your local authority wants you to follow, IMC or NFPA96 are typical. ETL is an organization that verifies test results by laboratories for various standards; an ETL stamp is a safety certification mark, not a requirement per se. IMC is a standard code which some AHJ may follow, mine follows NFPA 96.

Manufacturers will usually list their surface temperatures, another source is ASHRAE's Kitchen Ventilation section in its HVAC Applications manual. This lists equipment by duty category, or temperature, and recommends exhaust flow rates for each. Light duty 400F equipment includes electric or gas ovens, cheese melters. Medium duty 400F ovens would include hot top ranges, fryers, griddles. Heavy duty woul include open burner ranges, under-fired broilers, wok ranges. Extra heavy duty woud linclude solid fuel appliances. Exhaust flow rates are shown for different types of hoods (wall-mounted canopy, island, eyebrow, etc.) and for listed and unlisted hoods.

Manufacturers of "listed" exhaust hoods have had their hoods tested under standard conditions by a lab that is "listed" by an organization such as ETL or UL or CSA. They will provide the exhaust flowrates that their hoods require to properly get rid of fumes for each temperature range.

Good morning H2girl,

Thx for your note. The local governments historically have used the IMC, but recently have also used the ETL.

Your note prompted me to review ASHRAE's Kitchen Ventilation which says the NFPA conducted recents tests which resulted in their lowering their exhaust air velocity requirements from 1500'/m to 500'/m, which is what the IMC has always used (p42).

On the surface temperature issue, what would be ideal is an ETL list that shows the temperatures they use for each appliance. For example, other than going to the manufacturer, what is the surface temperature, & thus the cfm/lf requirement, of a 30" electric 20-gallon tilt kettle?

ASHRAE lists steam-jacketed kettles as light duty. That sounds similar enough to the tilt kettle, so I would use my engineering judgement and classify it as light duty 400F, requiring 200cfm/lf for an unlisted wall canopy hood, and 150 to 200 cfm/lf for a listed hood. Other hood styles may require more cfm...

On the other hand, if you know the usage will involve a less than ideal configuration under the hood, e.g. placement at the end of the hood without overhang, with no end wall on the hood, then you might choose to increase the flowrate.

Good morning again H2girl.

Thx again for your well-thought-out response.

What I would like avoid is a plans-checker questioning my classification of a particular appliance, or worse, my specifying an exhaust flow that's too low for the appliance.

Since the ETL system is based on surface temperatures, I would like to see a chart on which is listed the surface temperatures of all appliances. But I guess that depends on the manufacturer of a given appliance.

To further illustrate my struggle with this issue, I compared your classification of a cheese melter as a Light Duty appliance, with one made by another professional in the business, which placed the unit in a Heavy Duty class. So it seems very arbitrary to me. I would like something more precise.

I took cheesemelter from ASHRAE's table, I suspect your second opinion is for the salamander broiler, which ASHRAE lists as heavy duty, and which is also used for melting cheese and broiling foods. Different appliances, different uses. Confusing, I know. Obviously, you need to make sure everyone is using the same terminology.

I think you need to check each appliance with more than one source, to determine what it is used for and where is falls in the ASHRAE table or whatever table you use. Ask a restaurant cook, ask another engineer or technical person, send a post to CR4. Then you can have some confidence in your answer. But definitely get the make and model of the actual appliance that will be under the hood whenever you can, because manufacturer's info will give you certainty. You can't design a hood unless you know what equipment is going under it.

Good afternoon H2girl.

Is there any way you could scan that ASHRAE list to me?

Thx.

I am not sure about copyright laws or fair use provisions, so I would rather not. But you may find a copy on the internet, or you could search for "CKV design guide", which is a free commercial kitchen design guide which has a table included based on ASHRAE. Halton also has a design guide, no table I just checked. Greenheck also has a design guide with table.