Tag: hazard

UL Hazardous Locations Class 2 Division 1

Published on by Jordan T ShouseLeave a comment

Per the National Electrical Code (NEC) there are (3) classifications for areas that are defined as hazardous.  They are Class I (gases & vapors), Class II (flammable dust) & Class III (fibers). The focus of today’s Blog is on Class II locations.

Class II locations are those that are hazardous because of the presence of combustible dust. Note that the dust must be present in sufficient quantities for a fire or explosion hazard to exist. The fact that there is some combustible dust present does not mean a Class II hazardous location exists. Dust is defined as a combustible material that must exist as a finely divided solid of 420 microns (0.420 mm) or less. This will allow the dust to pass through a No. 40 sieve.  Just as in Class I, Division 1 and 2, the subdivision of Class II into Divisions 1 and 2 identifies the likelihood that there is an explosion hazard.

Division 1 locations are defined as an area where the amount of combustible dust is either suspended in the air or accumulated on surfaces in a sufficient concentration to allow for ignition.  The ignition could be caused by a failure or malfunction of the equipment in the classified area.  Group E & F dust (see chart below) is considered conductive and could penetrate into electrical equipment such as electric motors, control panels, electrical panels, etc., and cause an electrical failure.

Chart1

Group E dusts are metal dusts, such as aluminum and magnesium. In addition to being highly abrasive, and likely to cause overheating of motor bearings if it gets into them. Group E dusts are also electrically conductive and if they are allowed to enter an enclosure, can cause an electrical failure.

Chart2

Group F dusts are carbonaceous. The primary dust in this group is coal dust. Coal dust has a lower ignition temperature than those in Group E. While Group F dust has a higher thermal insulating value than the layer of Group E.  Therefore Group F requires more control of the temperature on the surfaces that the dust settles on. Group E dusts are semi-conductive, however if the voltages are 600 volts or less it is not generally considered a factor.

Chart3

Group G dusts include plastic dust, most chemical dust and food-grain dust. They are not electrically conductive. Generally, these dusts have the highest thermal insulating characteristics and the lowest ignition temperatures. Therefore, the equipment used in Group G areas must have the lowest surface temperatures to prevent ignition of a layer.

Chart4

Lastly, equipment rated for use in Classified Environments has a rating called the Temperature Code or “T-Code”.  This is the temperature or rather, temperature range that the rated device will operate normally and/or in a failed or failing state.  Consider something as common as a light fixture, electric motors, etc., as they could become hot enough to cause ignition depending on the type of dust in the area.  So be sure to check the “T-Codes” for every piece of equipment that will be used within a Classified Environment.

Chart5

When you are looking for expert advice on Hazardous Location Cabinet Coolers or safe, quiet and efficient point of use compressed air products give us a call.   We would enjoy hearing from you.

Jordan Shouse
Application Engineer

Send me an Email
Find us on the Web 
Like us on Facebook
Twitter: @EXAIR_JS

Hazardous Locations – Class 2 Div 1, Groups E, F & G 

Published on by Jordan T ShouseLeave a comment

Per the National Electrical Code (NEC) there are (3) classifications for areas that are defined as hazardous.  They are Class I (gases & vapors), Class II (flammable dusts) & Class III (fibers), the focus of today’s Blog is on Class II locations.

Class II locations are those that are hazardous because of the presence of combustible dust. Note that the dust must be present in sufficient quantities for a fire or explosion hazard to exist. The fact that there is some combustible dust present does not mean a Class II hazardous location exists. Dust is defined as a combustible material that must exist as a finely divided solid of 420 microns (0.420 mm) or less. This will allow the dust to pass through a No. 40 sieve.  Just as in Class I, Division 1 and 2, the subdivision of Class II into Divisions 1 and 2 identifies the likelihood that there is an explosion hazard.

Division 1 locations are defined as an area where the amount of combustible dust is either suspended in the air or accumulated on surfaces in a sufficient concentration to allow for ignition.  The ignition could be caused by a failure or malfunction of the equipment in the classified area.  Group E & F dust (see chart below) are considered conductive and could penetrate into electrical equipment such as electric motors, control panels, electrical panels, etc., and cause an electrical failure.

Chart1

Group E dusts are metal dusts, such as aluminum and magnesium. In addition to being highly abrasive, and likely to cause overheating of motor bearings if it gets into them. Group E dusts are also electrically conductive and if they are allowed to enter an enclosure can cause an electrical failure.

Chart2

Group F dusts are carbonaceous, the primary dust in this group is coal dust. Coal dust has a lower ignition temperatures than those in Group E.  While Group F dust has a higher thermal insulating value than the layer of Group E.  Therefore Group F requires more control of the temperature on the surfaces that the dust settles on. Group E dusts are semi-conductive, however if the voltages are 600 volts or less it is not generally considered a factor.

Chart3

Group G dusts include plastic dusts, most chemical dusts and food-grain dusts. They are not electrically conductive. Generally these dusts have the highest thermal insulating characteristics and the lowest ignition temperatures. Therefore, the equipment used in Group G areas must have the lowest surface temperatures to prevent ignition of a layer.

Chart4

Lastly, equipment rated for use in Classified Environments have a rating called the Temperature Code or “T-Code”.  This is the temperature or temperature range that the rated device will operate normally and/or in a failed or failing state.  Consider something as common as a light fixture, electric motors, etc., as they could become hot enough to cause ignition depending on the type of dust in the area.  So be sure to check the “T-Codes” for every piece of equipment that will be used within a Classified Environment.

Chart5

When you are looking for expert advice on Hazardous Location Cabinet Coolers or safe, quiet and efficient point of use compressed air products give us a call.   We would enjoy hearing from you.

Jordan Shouse
Application Engineer

Send me an Email
Find us on the Web 
Like us on Facebook
Twitter: @EXAIR_JS

NIOSH Hierarchy of Controls

Published on by Jordan T ShouseLeave a comment

Last year I hosted a Webinar about the NIOSH Hierarchy of Controls and compressed air safety! You can watch that here on our website!

The hierarchy of controls is a strategy that originates from NIOSH (National Institute for Occupational Safety and Health). NIOSH is the federal agency responsible for conducting research and making recommendations for the prevention of work-related injury and illness. This hierarchy is their recommendation for increasing safety for personnel by taking specific steps and how each step increases safety moving from bottom to top of the pyramid. In this blog I will explain the main elements of the HIERARCHY OF CONTROLS and illustrate how to reach the highest level of control with important compressed air safety standards.

Hierarchy of Controls

The least effective methods are Administrative Controls and Personal Protective Equipment (PPE). Administrative Controls involve making changes to the way people perform the work and promoting safe practices through training. The training could be related to correct operating procedures, keeping the workplace clean, emergency response to incidents, and personal hygiene practices, such as proper hand washing after handling hazardous materials. PPE is the least effective method because the personnel themselves make the choice to wear them or not wear them in any particular situation. They can be trained on the risks of not using PPE equipment (ear plugs, gloves, respirators, etc.) but we all know it does not always get used. PPE can also become damaged, may be uncomfortable and not used, or used incorrectly.

In the middle range of effectiveness is Engineering Controls. These controls are implemented by design changes to the equipment or process to reduce or eliminate the hazard. Good engineering controls can be very effective in protecting people regardless of the the actions and behaviors of the workers. While higher in initial cost than Administrative controls or PPE, typically operating costs are lower, and a cost saving may be realized in the long run.

The final two, Elimination and Substitution are the most effective but can be the most difficult to integrate into an existing process. If the process is still in the design phase, it may be easier and less expensive to eliminate or substitute the hazard. Elimination of the hazard would be the ultimate and most effective method, either by removing the hazard altogether, or changing the work process so the hazard is no longer part of the process.

EXAIR can help your company follow the Hierarchy of Controls, and eliminate, or substitute the hazards of compressed air use with relative ease. 

Home of Intelligent Compressed Air Products

Engineers can eliminate loud and unsafe pressure nozzles with designs that utilize quiet and intelligent compressed air products such as Air Nozzles, Air Knives and Air Amplifiers. Also, unsafe existing products such as air guns, can be substituted with EXAIR engineered solutions that meet the OSHA standards 29 CFR 1910.242(b) and 29 CFR 1910.95(a).

Elimination and Substitution are the most effective methods and should be used whenever possible to reduce or eliminate the hazard and keep people safe in the workplace. EXAIR products can be easily substituted for existing, unsafe compressed air products in many cases. And to avoid the hazard altogether, remember EXAIR when designing products  or processes which require compressed air use for cooling, cleaning, ejection, and more. 

If you have questions about the Hierarchy of Controls and safe compressed air usage from any of the 15 different EXAIR Intelligent Compressed Air® Product lines, feel free to contact EXAIR and myself or any of our Application Engineers can help you determine the best solution

Jordan Shouse
Application Engineer

Send me an Email
Find us on the Web 
Like us on Facebook
Twitter: @EXAIR_JS

Hierarchy of Controls Image:  used from  Public Domain

EXAIR and the Hierarchy of Controls

Published on by Jordan T ShouseLeave a comment

The CDC (Center for Disease Control) published a useful guide called “Hierarchy of Controls” that details (5) different types of control methods for exposure to occupational hazards while showing the relative effectiveness of each method.

NIOSH_Hierarchy_of_Controls
Hierarchy of Controls

 

The least effective methods are Administrative Controls and Personal Protective Equipment (PPE). Administrative Controls involve making changes to the way people perform the work and promoting safe practices through training. The training could be related to correct operating procedures, keeping the workplace clean, emergency response to incidents, and personal hygiene practices, such as proper hand washing after handling hazardous materials. PPE is the least effective method because the equipment (ear plugs, gloves, respirators, etc.) can become damaged, may be uncomfortable and not used, or used incorrectly.

In the middle range of effectiveness is Engineering Controls. These controls are implemented by design changes to the equipment or process to reduce or eliminate the hazard. Good engineering controls can be very effective in protecting people regardless of the the actions and behaviors of the workers. While higher in initial cost than Administrative controls or PPE, typically operating costs are lower, and a cost saving may be realized in the long run.

The final two, Elimination and Substitution are the most effective but can be the most difficult to integrate into an existing process. If the process is still in the design phase, it may be easier and less expensive to eliminate or substitute the hazard. Elimination of the hazard would be the ultimate and most effective method, either by removing the hazard altogether, or changing the work process so the hazard is no longer part of the process.

EXAIR can help your company follow the Hierarchy of Controls, and eliminate, or substitute the hazards of compressed air use with relative ease. 

Home of Intelligent Compressed Air Products

Engineers can eliminate loud and unsafe pressure nozzles with designs that utilize quiet and intelligent compressed air products such as Air Nozzles, Air Knives and Air Amplifiers. Also, unsafe existing products such as air guns, can be substituted with EXAIR engineered solutions that meet the OSHA standards 29 CFR 1910.242(b) and 29 CFR 1910.95(a).

In summary, Elimination and Substitution are the most effective methods and should be used whenever possible to reduce or eliminate the hazard and keep people safe in the workplace. EXAIR products can be easily substituted for existing, unsafe compressed air products in many cases. And to avoid the hazard altogether, remember EXAIR when designing products  or processes which require compressed air use for cooling, cleaning, ejection, and more. 

If you have questions about the Hierarchy of Controls and safe compressed air usage from any of the 15 different EXAIR Intelligent Compressed Air® Product lines, feel free to contact EXAIR and myself or any of our Application Engineers can help you determine the best solution.

Jordan Shouse
Application Engineer

Send me an email
Find us on the Web 
Like us on Facebook
Twitter: @EXAIR_JS

 

Hierarchy of Controls Image:  used from  Public Domain