Frequently Asked Questions (F.A.Q's)




Company Information
1. Where is Gemini Air Systems located?
2. What is the telephone number for Gemini Air Systems?
3. What is the Facsimile number for Gemini Air Systems?
4. What is the email address for Gemini Air Systems?
5. Is Gemini Air Systems Incorporated?
6. Are Gemini Air Systems Hoods Listed by Underwriters Laboratories?
7. Are Gemini Air Systems Baffle Type Grease Filters U.L. Classified?
8. Are Gemini Air Systems (Grease Guzzler) High Velocity Adjustable Slot Cartridge Grease Filters U.L. Classified?
9. Is Gemini Air Systems an NSF approved factory?
Kitchen Ventilation Hoods
10. What is a Kitchen Exhaust Hood?
11. When do I need A Kitchen Ventilation Hood?
12. Are their different Types of Hoods used for different Types of Heat-Processing Equipment?
13. What is a Type I Hood?
14. What is a Type II Hood?
15. What is an Exhaust Only Hood?
16. What is a Compensating Hood?
17. What is a Supply Air Hood?
18. What is a Plenum?
19. How do I determine the amount of Air that needs to be Exhausted from My Hood?
Ducts
20. What is an Air Duct?
21. What Type of Duct does a Type I Hood designed for Grease and Smoke removal require?
22. What Type of Duct does a Type II Hood require?
23. What determines the size of the exhaust duct for a Type I Hood?
24. What determines the number of and location of Type I exhaust duct(s)?
25. Do hoods over 12 foot in length require 2 exhaust ducts?
26. Does Gemini Air Systems manufacture exhaust hoods over 12 foot in length that require only 1 exhaust duct?
27. Does the exhaust duct have to located in the center of the hood plenum?
Fire Suppression
28. What is a Restaurant hood pre-engineered fire suppression system?
29. When is a fire suppression system required?
30. Does the installation of a Fire Suppression System require a permit?
31. How is a hood Fire Suppression system actuated?
32. Does the Gas and Electricity need to be shut down when the Fire Suppression system actuates?
33. Does the supply fan need to be shut down when the Fire Suppression System actuates?
34. Does the Exhaust fan need to be shut down when the Fire Suppression System actuates?
35. Is a Gas shut off valve required?
36. Who installs the Gas shut off valve?
37. Is an Electricity shut off switch required?
38. Who installs the Electricity shut off switch?
39. How does the electricity shut down on a Gas system?

1. Where is Gemini Air Systems located?

Gemini Air Systems is located at 1742 Sabre Street in Hayward, California, 94545. ( Back to top )

2. What is the telephone number for Gemini Air Systems?

To call the corporate office of Gemini Air Systems dial 510-670-9090 or 888-343-6464. To contact a sales person in your area click here. ( Back to top )

3. What is the Facsimile number for Gemini Air Systems?

The facsimile number for the Gemini Air Systems corporate office is 510-670-9055. ( Back to top )

4. What is the email address for Gemini Air Systems?

The email address for Gemini Air Systems is_________. ( Back to top )

5. Is Gemini Air Systems Incorporated?

Gemini Air Systems is a d.b.a. that Gemini Steel Incorporated utilizes for the its kitchen ventilation division Gemini Steel Incorporated is California Corporation.( Back to top )

6. Are Gemini Air Systems Hoods Listed by Underwriters Laboratories?

Gemini Air systems offers several different designs of Hoods, some of our Hood designs are U.L. listed and some are not. The Gemini Air Systems Hoods that are U.L. listed will be clearly marked on the web-site. ( Back to top )

7. Are Gemini Air Systems Baffle Type Grease Filters U.L. Classified.

Yes. All Gemini Air Systems Baffle Type Grease Filters are U.L. Classified to Standard #1046. ( Back to top )

8. Are Gemini Air Systems (Grease Guzzler) High Velocity Adjustable Slot Cartridge Grease Filters U.L. Classified?

Yes. All Gemini Air Systems (Grease Guzzler) High Velocity Adjustable Slot Cartridge Grease Filters are U.L. Classified to Standard #1046. ( Back to top )

9. Is Gemini Air Systems an NSF approved factory?

Yes. Gemini Air Systems is a NSF approved factory. Gemini Steel Inc, is approved under Food Equipment Standard #2 custom equipment manufacturer to mark Gemini Air systems and Gemini Stainless products with the NSF label. ( Back to top )

10. What is a Kitchen Exhaust Hood?

A Kitchen Ventilation Hood is an air-intake device that is first, designed to capture vapors, fumes, smoke, steam, heat or odors from commercial food and heat-processing equipment, and second remove the captured matter by means of a mechanical exhaust system. ( Back to top )

11. When do I need A Kitchen Ventilation Hood?

The Uniform Mechanical Code states that a Kitchen Ventilation Hood is required when a Food Processing Establishment uses Heat-Processing equipment for food or utensils which produces grease, vapors, steam, fumes, smoke, or odors. A Food Processing Establishment for the purpose of the Mechanical Code is defined as any building or portion thereof used for the processing of food but shall not include a dwelling unit. You should consult with the local Authority having jurisdiction if you are in question as whether your application requires a Kitchen Ventilation Hood. ( Back to top )

12. Are their different Types of Hoods used for different Types of Heat-Processing Equipment?

There are two Types of Hoods that are commonly referred to in most Mechanical Codes. One is a TYPE I Hood and the other is a TYPE II Hood. ( Back to top )

13. What is a Type I Hood?

A Type I Hood is a Hood that is designed for collecting and removing vapors, steam, fumes, odors and GREASE and SMOKE produced by Heat-Processing Equipment. ( Back to top )

14. What is a Type II Hood?

A Type II Hood is a Hood that is designed for collecting and removing vapors, steam, fumes, and odors produced by Heat-Processing Equipment. A Type II Hood Should NOT be used over Heat-Processing Equipment that produces Grease or Smoke. ( Back to top )

15. What is an Exhaust Only Hood?

An Exhaust only Hood is a Hood that is designed for collecting and removing vapors, steam, fumes, odors and sometimes GREASE and SMOKE produced by Heat-Processing Equipment. An Exhaust Only Hood has only one plenum designed for the sole purpose of Exhausting Air. An Exhaust Only Hood does not have any additional plenums built into it to accommodate make-up air. ( Back to top )

16. What is a Compensating Hood?

A compensating Hood is a Hood that has an outside air supply that is mechanically delivered to a plenum built as a part of the Hood for the purpose of delivering air below or within the Hood Cavity.( Back to top )

17. What is a Supply Air Hood?

A Supply Air Hood is a Hood that has an outside air supply that is mechanically delivered to a plenum built as a part of the Hood for the purpose of delivering air back into the Kitchen, but Not Below or Within the Hood Cavity. ( Back to top )

18. What is a Plenum?

A Plenum is an enclosure that is designed to contain Exhaust or Supply Air of different pressure levels for removal or delivery. ( Back to top )

19. How do I determine the amount of Air that needs to be Exhausted from My Hood?

The amount of Air that needs to be exhausted will be determined by the Gemini Air Systems Hood Series that you select and the size and type of Cooking Equipment you intend to operate under the Hood. Gemini Air Systems has a several different series of Hoods that have been listed by Underwriters Laboratories to determine minimum exhaust air levels. These Minimum Exhaust air levels are based on a Cubic Feet per Minute (cfm) formula multiplied by the length of the Hood. To determine the amount of Exhaust Air you will require:

1. Select the Gemini Air Series Hood that best fits your Ventilation and Architectural Requirements. Click here for assistance.

2. Determine the total length of the cooking equipment to be operated under the Hood.

3. Add all required additional Hood overhangs (if any) to the total equipment length to determine the minimum overall length of the Hood.

4. Select the Hood model by determining the maximum cooking temperature of the piece of Cooking Equipment that has the HOTTEST cooking temperature. The Hood Model number is equal to the minimum cfm/ft formula.

5. Multiply the Hood Model Number by the Hood Length using the cfm/ft formula.

*Note. Note the above formula is a guide to form an approximation of the required Hood Exhaust Air amount for Gemini Air Systems U.L. Listed Hoods, however certain conditions either foreseen or unforeseen may require greater Exhaust and/or lessor supply air flow rates for complete vapor and smoke removal in specific installations. Consult the factory before engineering decisions are made or equipment is purchased for additional information. ( Back to top )

20. What is an Air Duct?

An Air Duct is a passageway through which Air flows. ( Back to top )

21. What Type of Duct does a Type I Hood designed for Grease and Smoke removal require?

The Uniform Mechanical Code states that a Type I Hood must have a duct that is specifically designed for Grease laden air. The duct shall be constructed of at least. o55-inch-thick (1.40mm) ( No. 16 manufacture's standard gage) steel or stainless steel at least .044 inch (1.10mm) in thickness continuously welded and water tight. You should consult with the Local Authority Having Jurisdiction for information regarding Type I duct requirements in your area prior to any engineering decisions or fabrication. ( Back to top )

22. What Type of Duct does a Type II Hood require?

The Uniform Mechanical Code states that a Type II Hood must have a duct that is constructed of rigid metallic materials of al least 0.024-inch (.0.61) (No.24 gage) thick. You should consult with the Local Authority Having Jurisdiction for information regarding Type II duct requirements in your area prior to any engineering decisions or fabrication. ( Back to top )

23. What determines the size of the exhaust duct for a Type I Hood?

The size of the exhaust duct of a Type 1 Hood is determined by the amount of air that will be exhausted and the speed at which that air will be moving. The Uniform Mechanical Code states that a duct system serving a Type I Exhaust hood must be sized in such a manner to provide an air velocity within the duct system of not less than 1500 feet per minute or greater than 2500 feet per minute. ( Back to top )

24. What determines the number of and location of Type I exhaust duct(s)?

The Uniform Mechanical Code states that an exhaust duct with in a Type I hood shall be located as to optimize the capture of particulate matter. Each outlet shall serve not more than a ***12-foot*** section of hood. **EXCEPTION** Listed exhaust hoods are to be installed in accordance with the terms of their listing and the manufactures installation instructions.
(CLICK HERE) to view a list of Gemini Air Systems U.L. listings.( Back to top )

25. Do hoods over 12 foot in length require 2 exhaust ducts?

Not always, some hoods receive a listing that allows the manufacturer to manufacture hoods longer that 12 feet in length that only require 1 exhaust duct. ( Back to top )

26. Does Gemini Air Systems manufacture exhaust hoods over 12 foot in length that require only 1 exhaust duct?

Yes, Gemini Air Systems manufactures several different series of hoods that have been listed by Underwriters Laboratories to be installed in lengths exceeding 12 feet. (CLICK HERE) to view a list of Gemini Air Systems U.L. listings. The listings show the series of hoods and the maximum length a hood may manufactured with exhaust duct. ( Back to top )

27. Does the exhaust duct have to located in the center of the hood plenum?

The Uniform Mechanical Code states that an exhaust duct with in a Type I hood shall be located as to optimize the capture of particulate matter. Each outlet shall serve not more than a ***12-foot*** section of hood. **EXCEPTION** Listed exhaust hoods are to be installed in accordance with the terms of their listing and the manufactures installation instructions.
(CLICK HERE) to view a list of Gemini Air Systems U.L. listings. ( Back to top )

28. What is a Restaurant hood pre-engineered fire suppression system?

A pre-engineered fire suppression system is a utility shut down and extinguishing agent distribution system that is designed for protecting the hood, plenum, exhaust duct, grease filters, and cooking appliances from grease fires. ( Back to top )

29. When is a fire suppression system required?

The General rule is that fire suppression system is required in all Type I Hood applications. You should consult the Authority Having Jurisdiction in all cases for clarity on when a Hood Fire suppression system is required or not required. ( Back to top )

30. Does the installation of a Fire Suppression System require a permit?

Yes, a permit issued for the installation of a hood system usually will not encompass the fire suppresion system. A separate permit specifically for the fire suppresion system will be required. This usually will require submitting drawings of the pre-engineered system to the local Authority Having Jurisdiction well in advance of the test and the restaurant opening for issuance of a permit. Before a fire suppression system can be activated and made ready for use the local Authority Having Jurisdiction will need to witness a test of the functionality of the system. The system installer should perform this test. ( Back to top )

31. How is a hood Fire Suppression system actuated?

The hood Fire Suppression system can be automatically actuated via fusible links or manually actuated via manual pull stations. ( Back to top )

32. Does the Gas and Electricity need to be shut down when the Fire Suppression system actuates?

Yes, all Gas or electricity will need to be shut down that powers the equipment under the hood underneath the hood, in addition any/all electricity that is located under the hood also needs to shut down. In some cases Supply Fans, Exhaust Fans, Supply and Exhaust Fans or other equipment may be required to shut down upon the Fire Suppression system actuation. Consult the local Authority Having Jurisdiction for the requirements in you area! ( Back to top )

33. Does the supply fan need to be shut down when the Fire Suppression System actuates?

In some cases Supply Fans, Exhaust Fans, Supply and Exhaust Fans or other equipment may be required to shut down upon the Fire Suppression system actuation. Consult the local Authority Having Jurisdiction for the requirements in you area! ( Back to top )

34. Does the Exhaust fan need to be shut down when the Fire Suppression System actuates?

In some cases Exhaust Fans, Supply Fans, Exhaust and Supply Fans or other equipment may be required to shut down upon the Fire Suppression system actuation. Consult the local Authority Having Jurisdiction for the requirements in you area! ( Back to top )

35. Is a Gas shut off valve required?

A gas shut off valve will be required anytime that gas is used to power the cooking equipment under the hood in which the Fire Suppression System is installed. ( Back to top )

36. Who installs the Gas shut off valve?

A Gas shut off valve will be supplied to you upon the purchase of the system if it required. It the responsibility of the owner to have a properly licensed contractor install the Gas valve at their sole cost. Consult the factory or factory Authorized Fire Suppression system installer for the proper location and installation instructions. ( Back to top )

37. Is an Electricity shut off switch required?

An Electricity shut off switch will be required anytime that electricity is used to power the equipment under the hood in which the Fire Suppression System is installed. Exhaust Fans ( Back to top )

38. Who installs the Electricity shut off switch?

An electricity shut off switch will be supplied to you upon the purchase of the system if it required. It the responsibility of the owner to have a properly licensed contractor install the electricity switch at their sole cost. Consult the factory or factory Authorized Fire Suppression system installer for the proper location and installation instructions. ( Back to top )

39. How does the electricity shut down on a Gas system?

The Fire suppression system will be supplied with a micro switch that is to be connected to a contactor that when actuated will shut down the electricity that is required to be shut down during the Fire Suppression system actuation. It the responsibility of the owner to have a properly licensed contractor install the contactor and all wiring and conduit and any other materials at their sole cost. Consult the factory or factory Authorized Fire Suppression system installer for the proper location and installation instructions. ( Back to top )