Category Archives: Designed Kitchen Exhaust System

A properly designed kitchen exhaust hood system

Installation, Operation, and Maintenance of Commercial Kitchen Hoods

Installation, Operation, and Maintenance of Commercial Kitchen Hoods

ROOF TOP PACKAGE SYSTEM, MAKE-UP AIR AND EXHAUST FANS

1. Air intake filters should be cleaned monthly or more often if conditions dictate.

2. Check all belts for slippage and tighten if necessary.

3. Perform cleaning on the exhaust fan interior and wheel as required to prevent accumulation of grease that could lead to a fire hazard.

4. At least every six months, all electrical connections should be inspected and checked for tightness.

5. Oil and/or grease all motors and bearings every six months or as conditions dictate.

6. If supplied with job, check and empty grease collection cup on outside of exhaust fan.

CLEANING AND MAINTENANCE OF STAINLESS STEEL HOODS

1. Carefully wipe away gritty substances clinging to stainless steel surfaces to avoid scratching.

2. Dilute 1/2 cup of laundry detergent (E.G. Tide, Surf) with 1 gallon warm water.

3. Soak a cloth in the water detergent solution. Wring out excess.

4. Rub the cloth in the direction of the grain.

5. Wipe stainless steel with cloth soaked in warm water to remove all traces of the cleansing agent.

6. Wipe stainless steel dry with a clean cloth.

7. Reapply stainless steel polish (E.G. Sheila Shine).

8. Empty and clean grease drain and cups.

9. Filters should be cleaned in a dishwasher or soak sink periodically.

CAUTION

DO NOT use iron wool (Brillo Pads), scrapers, or spatulas to clean hood!

DO NOT use the following substances on or around the hood!

1. Chlorine or chlorine based substances.

2. Acids (E.G. acetic, hydrochloric, sulfuric).

3. Chloride based substances (E.G. mercuric chloride, ferric chloride).

Vapors of the above substances can corrode stainless steel!

Operation of Hood

Before turning on cooking equipment, make sure that the make-up air and exhaust fans are on. Leave fans on at least 30 minutes after cooking equipment is shut off. Clean hood daily with non-abrasive cleaners.

Remove filters and run through dishwasher daily.

Semi-Annually: Fire suppression system must be inspected by local, qualified fire system distributor.

For more in-depth details call for a free consultation.

Contact us today 1-800.932.1969

A properly designed kitchen exhaust hood system

A properly designed ventilation system is an important part of any kitchen.

It should give a smoke-free environment while maintaining a comfortable working temperature for kitchen staff. Choosing the right hood ventilation system is very important when it comes to operating a safe and efficient kitchen.

Style, size and exhaust rate are among the factors to consider when specifying the proper hood system for a facility.

Equipment Layout

The type of equipment that will be installed underneath the hood system and where the hood is located will affect both the exhaust rate and decide how much makeup air is required to keep up a balanced kitchen.

Providing a clear picture of the kitchen floor plan and the layout of the cooking equipment helps the design engineer understand what size hood is required as well as the exhaust air measure.

It also helps the engineer clarify where the exhaust duct should be and what will be required in a fire protection system. If equipment schedule and kitchen floor plans are not available, offer a list of cooking equipment with sizes from left to right and verify if walls are located around the hood.

In addition, specify whether the cooking equipment is gas or electric to find out if a gas valve is needed for the fire system Ceiling Specifications.

Provide the design engineer with the ceiling height to decide if a standard height ventilator will fit within the space or if enclosure panels will be required.

The joist height will also help find out what style of ventilator to use, whether the duct work can be above the hood and where the utility connections should be Current Ventilation Code.

Ventilation standards vary from state to state and even from county to county. There are variations of the National Fire Protection Association (NFPA) and the American Society of Heating, Refrigerating and Air-Conditioning (ASHRAE) codes as well, so it is important to find each client’s ventilation code System Balance.

Managing the interaction between HVAC, makeup air and exhaust hoods is important, as the amount of makeup air produced can directly affect the efficiency of kitchen ventilation.

Essentially, if too much air is taken out and not enough air comes in to replace it, a contaminated working environment is created and efficiency is reduced.

The key to proper makeup air is site of discharge and the speed at which it is introduced into the space. It is important that the air is not forced toward the hood, but to allow the hood to draw what it needs when it needs it.

Identifying the proper exhaust rate depends upon three factors: the type and use of the cooking equipment under the hood, the style and geometry of the hood itself, and how the makeup air (conditioned or otherwise) is introduced into the kitchen.

No matter how hard a ventilation hood works, if it releases some captured air and grease back into the kitchen environment, then air quality in the kitchen is reduced.

Not only does sizing and installing the right hood reduce the overall ventilation exhaust rate, but it also ensures maximum capture of containment from cooking equipment.

When the right system is sized and selected, an operation can enjoy lower energy costs to heat or cool the kitchen as well as supply a more comfortable and productive environment for its employees.

The costs and risks of damper-based controls in kitchen ventilation

There is only one practical application for installing modulating dampers in high-temperature grease ducts over kitchen hoods serving commercial cooking equipment:

A high-rise building in an urban setting with a kitchen having multiple hoods totaling over 10,000 cfm located on a lower level where there is no other way to exhaust the effluent other than design a single chase and duct to a single fan on a higher level.

It is typically more cost-effective on a construction and operating basis, as well as less risk-prone from a liability standpoint, to decrease the length of high-temperature grease ducts.

This is why, such as, most hotel, hospital, and other large commercial kitchens are designed as part of a single-floor building and only connected to a multi-story building.

This design eliminates the first cost of installing a duct 2, 5, 10, or more floors, the waste of valuable space in a high-rise, and the risk of extending a potential fire hazard any further than necessary.

And it facilitates a dedicated fan per hood design without the need for dampers—the benefits of which will be explained later in this article.

But even in a high-rise building, purposely designing “obstructions” in a long, high-temperature grease duct that is otherwise designed to convey heat, smoke, and grease vapors out and away from the building is problematic for three reasons:

Liability concerns: The longer the high-temperature grease duct, the greater the probability of distributing grease into areas of the building beyond the kitchen. Because grease is a combustible substance, this poses a potential risk.

This is why codes need regular cleaning of kitchen hood, ducts, and fans. High-rise buildings with long ducts and obstructions are inherently more exposed from a liability standpoint than are single-story buildings with short ducts and no obstructions.

Energy penalties: Long ducts with multiple 90-deg turns and dampers add resistance to airflow and need the fan to work at a higher speed than otherwise necessary to move a specified air measure.

Given that one purpose of these dampers is to purportedly save fan energy, it is a step in the wrong direction. In fact, if the cooking load is fairly steady and/or the controls are not highly reliable, the long ducts, added 90-deg turns, and installed dampers will increase than decrease overall energy usage.

Maintenance issues: Modulating dampers are constantly cycling and have a limited number of cycles before they will eventually fail.

Even a million-cycle rating could be limited to a couple of years of operation depending on the variability of cooking operations and the effect of the heat, grease, and quarterly cleanings on their overall life.

No architect or engineer wants to have a damper fail in a high-rise building that is serving hundreds of employees, patients, and/or visitors.

Who will inspect, repair, and replace these relatively inaccessible devices before such an occurrence?

For more in-depth details call for a free consultation.

Contact us today 1-800.932.1969

Commercial Kitchen Exhaust Fan Maintenance

 

We all know the importance of providing our customers with the necessary services to assist them in realizing longevity from their commercial kitchen exhaust fan.

Lubrication of the kitchen exhaust fan bearings during the course of the job is one definite way to provide a genuine service to our customers – and it is a task which involves very little time and effort to accomplish.

Since our work regularly takes us onto the roof or into the mechanical penthouse, it makes good sense to provide the essential services such as bearing lubrication to kitchen exhaust fan while we are conducting operations.

Equally important to providing this type of service to our customers for their kitchen exhaust fan to realize a full life is the application of the correct medium of lubricant, in an amount sufficient to do the job right.

Manufacturers of kitchen exhaust fan type provide either lifetime lubricated (sealed), or lube-able type bearings on their equipment. Due to the higher rotation speeds and elevated temperatures with which this equipment is known to operate, chances are you will encounter the lube-able type more often than not.

The pre-lubricated type of kitchen exhaust fan will generally require no service under normal operating condition for seven to ten years, and then they will require replacement. The greaseable type of bearings will generally not require re-lubrication for the first six months of operation because they are most often lubricated at the factory.

Kitchen exhaust fan shaft bearings are best served by lubricating them with a blue lithium type grease applied with a manual grease gun. Excepting safety hazards, the shaft bearings are best lubricated with the shaft rotating, and the grease gun should be slowly pumped until a slight discharge of grease is observed at the lip of the grease seal.

Because bearings are precision made, the grease fitting nipple should always be wiped off prior to applying the grease gun to prevent forcible contamination of the unit.

Over lubrication will inevitably lead to premature failure of the bearings due to both the excessive volume of grease unseating the grease seals, allowing foreign matter to collect and contaminate the bearings, and elevated operating temperatures caused by friction as the overfilled bearings rotate at high speed.

Certain considerations should be made concerning the frequency of lubrication of shaft bearings. Generally speaking, an exhaust fan operating 12 hours per day would be best served by lubricating two to four times annually, provided the establishment is opened year round, and the above procedures are followed.

Decreasing the schedule should be considered if the establishment is seasonal, or operates fewer hours per day; increasing the schedule may be warranted if the fan is serving a high temperature system such as solid fuel cooking, or operating 24 hours per day.

Prevent accidental over-lubrication, and mixing of different types of greases, and know if the establishment maintenance staff are providing preventative maintenance of the fans regularly prior to your service commencing.

Electrical motors employing ball type bearings may as well be equipped with either sealed bearings or grease able bearings, however, motor bearings are considerably more sensitive and should be maintained only by staff familiar with the application.

Motors with lube able type ball bearings will either be equipped with a grease fitting, or a removable screw for applying grease. Similarly, most will also use grease relief screws which need removal to ease drainage of excessive grease during a 20 minute operating period after lubrication, and then the drain screw requires replacement.

As a general guide only, your average motor sizes 1 /8 to 7.5 horsepower will only need re-lubrication once every 5 years if operated 5,000 hours annually and equipped with lubrication points.

On units with grease nipples, only I to 2 strokes with a grease gun are required on NEMA frame sizes 215 and smaller, 2 to 3 strokes on NEMA 254 through NEMA 365.

If equipped with a screw type fitting, a 2 to 3 inch grease string should be applied to each bearing on NEMA size 215 and smaller, and a 3 to 5 inch string on larger motors. Again, drain plugs should be removed and the motor operated 20 minutes before replacement.

Motors should always be lubricated at a standstill. Their grease fittings must be cleaned before lubing. Also, only use clean grease obtained from a sealed container.

When possible, manufacturers’ recommendations should be followed when selecting the brand of lubricant to use on a motor, and extreme care should be used to ensure petroleum and silicone greases are not mixed.

Because most lubricants will deteriorate motor winding’s, they should never be over lubed!

More Info: 1-800-932-1969