Currently Browsing: kitchen ventilation

Demand Control Ventilation

Is Demand Control Ventilation required on all projects?

Demand Control Ventilation is a control system that varies the volume of exhaust (and supply) based on cooking activity. Since there are idle and peak periods for most cooking operations, the potential to save fan and HVAC energy is significant. ASHRAE 90.1 (American Society of Heating Refrigeration and Air Conditioning Engineers) establishes design standards for […]

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Pollution Control Unit

What is the difference between pollution control units?

Pollution Control units, also referred to as Scrubbers are systems that remove a high percentage of grease, vapor and odors from the cooking process through a means of filtration. The devices fall into 2 major categories, media filter type and electrostatic precipitators (ESP). Both systems have a form of odor abatement technology associated with them. […]

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air ceiling registers

How do replacement air ceiling registers affect the hood?

The placement and location of ceiling registers (diffusers) for the introduction of replacement air can have a direct impact on the proper operation of the exhaust hood. Diffusers that have been designed for commercial spaces, such as “four way diffusers” were developed to have a high induction capability. That means they discharge at a relatively […]

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Gas burning in the burner of gas oven

Why is a heat load based design important for kitchen hoods?

Establishing exhaust volumes for hoods had been an inexact science, primarily relying on U.L. values to establish exhaust rates. U.L. however clearly states that the minimum exhaust rates established during testing should not be used for design purposes since they were achieved in a laboratory environment. A greater exhaust might be required to provide proper […]

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Kitchen Ventilation Cooking Equipment

Why is cooking equipment makes and models important for preliminary engineering?

Outdated methods of ventilation design categorized appliances into different classes of light, medium, heavy duty and extra heavy duty (solid fuel). Average exhaust rates were established for each category based on rules of thumb, cfm per foot of hood. With the advent of U.L. 710 test, this morphed into minimum exhaust per surface temperature (400° […]

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SupplyAir

What temperature should the supply air be introduced to the Kitchen?

Engineers will typically design for a supply air temperature at 10 degrees above traditional occupied spaces outside of the kitchen. Supply air is usually brought into an occupied space at 57°F/14°C off the coil to mix with room air to maintain a specified space temperature at design conditions. In a kitchen, due to the air […]

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AHJ_766x511

Who is the “AHJ” and what authority do they have on a project?

AHJ refers to “The Authority Having Jurisdiction”. The AHJ has final authority for the interpretation of fire and building codes (NFPA, IMC). Although model codes are interepted fairly consistently, a number of municipalities may have variations or interpret certain elements of the codes differently. In some cases there are additions not covered in the model […]

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Heat Gain to Space

How heat sources differ in commercial kitchens than other commercial spaces

Mechanical engineers calculate cooling and heating loads for commercial spaces in order to size the ventilation systems. The type of space plays a key role in determining necessary ventilation requirements. Commercial kitchens are unique in they operate year round and cooling is almost always required, even during the colder winter months. This is due to […]

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KVOverhang

What are the standards for hood overhang to specific cooking equipment? Is it based on UL Listings of the hood?

The specific overhang (ends, front and/or rear) are predicated on the U.L. 710 testing for the specific model of that manufacturer. When testing for capture of visible cooking vapors, the manufacturer establishes the overhangs to test under (6” (152mm) on the ends for example). Assuming they pass the test, that overhang becomes part of their […]

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