In February of 1972 OSHA released a standard to improve worker safety when operating handheld compressed air devices being used for cleaning purposes. This directive focuses around human skins permeability. That is, if you were to take an open ended pipe that had compressed air being discharged over 30 psig it can actually push through the skin and create an air embolism.
OSHA’s Directive 29 CFR 1910.242(b)
Air Embolisms are extremely painful, and in extreme cases, can be deadly. The risk associated with an air embolism can be mitigated by following the OSHA directive and reducing the downstream pressure of an air nozzle or nozzle pressure below 30 psi for all static conditions. Dead ending is when the passageway for the air becomes blocked and turns a dynamic flow of air into a static flow. This is in the event the pipe, nozzle, lance, etc. becomes blocked by a human’s body. This is a directive that all Intelligent Compressed Air® products from EXAIR focus on meeting or exceeding.
Our Air Nozzles and Jets video shows a great depiction of how this can be achieved with our engineered design of nozzles. The recessed holes and the fact that there are multiple passages for the air to exit are easy to see on the nozzle. Products like the Super Air Knife may not be so easy to see but the way the air knife cap overlaps prevents the Super Air Knife from being dead ended in the event an operator comes into contact with the discharge air.
Even though this directive was created in 1972 it continues to be at the forefront of industrial environments. I have even been to a custom artwork facility that was effected by this standard because they would use a handheld blowgun to remove dust and debris before matting and framing artwork with glass. They also removed dirt and dust from the frames before paint. This wasn’t your typical manufacturing environment yet they were still held to the same standards and were made safe by implementing engineered solutions such as our Super Air Nozzle.
If you would like to discuss how we can help increase your operator safety and ensure you meet or exceed OSHA 29 CFR 1910.242(b), please contact an Application Engineer today.
Strings of numbers and characters can often appear daunting. For instance, if I wrote in binary code it would be a string of ones and zeros. (01000101 01101110 01100111 01101001 01101110 01100101 01100101 01110010 01101001 01101110 01100111 00100000 01101001 01110011 00100000 01000001 01010111 01000101 01010011 01001111 01001101 01000101.) That can look like gibberish and cause concern if unknown or it can make sense to programmers and people familiar with binary code.
Other alphanumeric strings may cause some concern for industry professionals. Take, for instance, OSHA standards. The OSHA standard 29 CFR 1910.95 (a) may be unfamiliar to some, and thus concerning. Many Environmental Health and Safety Engineers will recognize this code. It is an OSHA standard that revolves around the amount of time an employee is permitted to be exposed to specific sound levels. These sound levels are all based on the weighted sound level of the noise the operators are exposed to. To better understand how the octave and frequency of the sound play into this, there is a chart provided below.
Equivalent A-Weighted Sound Level Chart – (1)
The weighted sound level is the level at which a Digital Sound Level Meter will read the current level of noise within an environment. This scale is then used to move further into the OSHA directive that we focus on helping companies meet to best provide safe environments for their employees to work in.
If you notice, the lowest weighted sound level is 90 dBA, this is also the lowest-rated noise level that OSHA speaks of in 1910.95(b)(2). It has been shown that noise levels over this level for extended periods will result in permanent hearing loss. The standard then goes on to discuss the duration an employee can be exposed to noise levels even with the use of personal protective equipment as well as even impulsive or impact noise. The table of permissible time limits is shown below.
Permissible Noise Exposures (2)
As you can see from the table above provided by OSHA, any noise level that an operator is exposed to for eight hours cannot exceed 90 dBA. Noises within an industrial environment can also be variable throughout the day. For instance, the operator stands outside of a sheet metal press and the concussive strike on the press gives off a 90 dBA strike for every stroke of the press. This would not be a continuous noise level. Maybe the operator is operating a CNC machine that is cutting a nest of parts and uses a handheld blowgun to remove debris and coolant from the parts before taking them from their fixture. This blowgun is not used continuously and therefore would not be rated as such for the exposure time. A time study would be conducted on the average length of time the operator is utilizing this gun along with the level of noise it produces during use. OSHA then gives a calculation to use to appropriately combine the sound level while the gun is being used and when it is not in use. That equation is written out below.
Where:
C1 = Duration of time for a specified noise level
T1 = Total time of exposure permitted at that level
Cn = Total time of exposure at a specified noise level
Tn = Total exposure time permitted at that level
Should the summation of the fractions for different exposures be greater than the Total Exposure fraction, the summation value should be used. As mentioned above, a time study on exposure to noise levels will be needed to obtain the information needed for this type of study. Once the study is done the process can proceed to the next level within the OSHA standard which is a hearing conservation program.
I would like to interject a small side-step at this point. Rather than rolling straight into the implementation of PPE which is proven to be the lowest reliable factor of protection by the CDC and NIOSH. If any of these noise levels being generated are due to the use of compressed air points of use, EXAIR can potentially lower the noise of these point of use applications. In the events, open blowoffs or “band-aid” fixes are in place to keep processes running, and Engineered Solutions can easily be implemented that will reduce the noise level produced by this operation. Whether it is on the handheld Safety Air Gun in the hands of a CNC operator, or if it is a part/scrap ejector that is blowing the sheet metal press out after every strike, we have products that have proven time over time using an Engineered Solution will save air, reduce noise levels, and still get the job done.
If you would like to discuss OSHA directives revolving around compressed air, share with us a recent citation you received from an inspector for this standard, or just discuss compressed air usage in general, contact us.
