Ventilation is a critical element in the equipping of a pizza shop.
By national building code any cooking devise that can raise the temperature of product to 220 degrees is required to have a hood, be it gas or electrically heated. The object of hoods is to exhaust heat and cooking orders whatever the source of the heat.
Health and building departments have stringent rules as to the amount of air to be exhausted by various styles of hoods. It is also a requirement that the same amount of air exhausted from the building be brought back into the building at or near room temperature. The comfort level for workers and customers is also a factor for consideration.
The air that is brought back into the building is referred to as make up air. A properly ventilated building has slightly higher air pressure than outside air pressure. If outside air pressure is higher than inside doors are hard to open and when doors are opened outside air rushes in bringing dust, dirt, humidity,plus hot and or cold outside air in maks uncomfortable drafts. Gas fired appliances also can starve for oxygen and not operate properly. Cooking odors are retained in the building and other problems arise.
Recall the old description of many restaurants as greasy spoons? That was because without proper ventilation everything in the building felt greasy.
There are hoods that have been tested by Underwriter laboratories or others such as ETL. Hoods thus tested and certified require substantially less exhaust and make up air than unlisted hoods some times half as much. Less air exhausted = less A/C lost.
The required make up air can be provided in two ways. A separate make up air unit can be installed or sufficient air conditioning can be provided through the Heating & cooling system to supply the required make up air.
We prefer the use of listed hoods that extract little air from the building plus sufficient air conditioning, which is not great when these type hoods are used.
Initial cost of the listed hoods and sufficient air conditioning is about the same, or a little bit more, as the unlisted hoods and make up air systems .
There is a much better comfort level working with sufficient air conditioning and substantially less cost to operate each year. Rule of the thumb for make up air operating cost is $1.50 per CFM per year,for example, 2000 CFM = $3000.00 yr.
It should be noted that most buildings used for carry out-delivery pizza shops are about 20 ft wide 60 or 70 ft. long and are usually equipped, as an empty building, with a 5 -ton air conditioner. Those first five tons of air conditioning are just about enough to break even with the heat of the oven, heat from the various compressors and food warmers. It is what ever you add to those first five tons of air conditioning that cools your lobby and work area.
Usually we find that 10 to 12 tons or better of air conditioning is required to cool the average shop to tolerable working temperatures. Naturally larger sit down shops need More A/C.
In a few parts of the nation, where the temperature never falls very low and humidity is extremely low a simple filtered fan system that brings in outside air can be used. Unfortunately that type system brings in a lot of extremely hot air during the warmer part of the day and the air conditioning system cannot cope making the shop very uncomfortable to work in.
Most all makeup air system do not cool summer air, they just warm winter air, making the shop extremely hot in summer when super heated air off the roof is brought into the building.
In the very few, always warn and very dry, low humidity areas an evaporative cooler might be used. We do not recommend the athose types of make up air systems.
Hope this helps someone
George mills