Minimize Exposure to Hazards Using the Hierarchy of Controls

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.

HierarchyControls
CDC Hierarchy of Controls

The least effective methods are Administrative Controls and 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 (Personal Protective Equipment) 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 to the hazardous task is no longer performed.

EXAIR can help your company follow the Hierarchy of Controls, and eliminate, or reduce the hazards of compressed air usage.

Engineers can eliminate loud and unsafe pressure nozzles with designs that utilize quiet and pressure safe engineered 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).

Nozzles

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.

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.

Brian Bergmann
Application Engineer
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Understanding Decibels & Why OSHA Pays Attention to Your Noise Exposure

In the simplest of metric terms, a decibel is one-tenth of a bel.  But, historically, bel was a unit created to honor Alexander Graham Bell who invented the telephone.  In the early days with telephone wires, they noticed that the signal strength would decay over a long distance.  In order to determine power requirements to connect people for communications, they determined that they could use the ratio of power levels.  As a start, it had to be based on a minimum amount of power required for a person to hear on the telephone.  They found that the signal power level to generate an angular frequency of 5000 radians per second would be that minimum value as determined by an average number of people.  They used this mark as a reference point in the ratio of power levels.  Because of the large variations in values, they simplified the equation on a base-10 log scale and dividing the bel unit by 10.  Thus, creating the measurement of decibel.

Today, this same method is used to measure sound.  Like frequency waves that travel through the telephone wires, pressure waves travel through the air as sound.  This sound pressure is what our ears can detect as loudness, and it has a pressure unit of Pascals (Pa).  As an example, a small sound pressure would be like a whisper while a large sound pressure would be like a jet engine.  This is very important to know as high sound pressures, or loudness, can permanently damage our ears.

With sound pressures, we can determine the Sound Pressure Level (SPL) which is measured in decibels (dB).  Similar to the equation for the telephone power signals above, the SPL also uses a ratio of sound pressures in a base-10 logarithmic scale.  For a minimum reference point, an average human can just start to hear a sound pressure at 0.00002 Pa.  So, the equation for measuring sound levels will use this minimum reference point as shown in Equation 1.

Equation 1:

L = 20 * Log10 (p/pref)

where:

L – Sound Pressure Level, dB

p – Sound pressure, Pa

pref – reference sound pressure, 0.00002 Pa

Why is this important to know the decibels?  OSHA created a chart in 29CFR-1910.95(a) that shows the different noise levels with exposure times.  This chart was created to protect the operators from hearing loss in work environments.  If the noise level exceeds the limit, then the operators will have to wear Personal Protection Equipment (PPE), or suffer hearing damage.  EXAIR offers a Sound Level Meter, model 9104, to measure sound levels in decibels.  It comes calibrated to accurately measure the sound to determine if you have a safe work environment.

Sound Level Meter

There is a term that is used when it comes to loud noises, NIHL.  This stands for Noise Induced Hearing Loss.  Once hearing is damaged, it will not come back.  To keep your operators safe and reduce NIHL, EXAIR offers many different types of blow-off products that are designed to decrease noise to a safe level.  So, here’s to Alexander Graham Bell for creating the telephone which can be used to contact EXAIR if you have any questions.

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

 

Photo of Telephone by Alexas_FotosCC0 Create Commons

One Super Air Wipe doing the job of 3 Generic Air Wipes

Today, I had the opportunity to the work with a customer, who produces soft seals for the window and door industry. The soft seals are created through a multi-step process, where drying is critical for the overall quality of the product. After the extrusion of PPE (polyphenyl ethers) material, the seal is run through a water bath.  The next step is for the extruded PPE to be dried using compressed air.  After drying, a glue is applied to join the PPE soft seal to an aluminum frame.  If the PPE was not dry from the water bath, the glue would not bond the aluminum and soft seal together.

 

The customer wanted to replace their current compressed air drying system. The current system utilized (3) ceramic air wipes to dry off the PPE seal before the gluing process. He was relatively new to the company or the particular line, so he did not have all the history for the production line during our conversation. We were both wondering why three consecutive air wipes were used when one air wipe should be getting the job done, but we never could figure it out regardless. I pointed out that one EXAIR Super Air Wipe will clean off a variety cross sections in one pass. The old air wipes used 7.6 SCFM of compressed air for each air wipe or a total air flow of 22.8 SCFM to dry the rubber seal. Also, the old air wipes created 80 dB of noise. A correctly sized 1/2″ EXAIR Super Air Wipe would lower that noise to 75 dBA and lower the total air consumption to 13.9 SCFM.

AirWipe

By replacing three inferior ceramic wire dryers with one EXAIR model 2400 Super Air Wipe, the customer was able to get the job done better, reduce his noise level and save compressed air. EXAIR has the broadest line of problem solving compressed air products, if you have a problem area or an application you think we may be able to solve, please let us know. We are happy to assist.

Dave Woerner
Application Engineer
Davewoerner@EXAIR.com
@EXAIR_DW