Okay, I will admit, the title may be a tad bit leading. The fact is, it can be done. I speak to customers almost daily who are struggling with the noise levels produced from open pipe blowoffs. With Noise Induced Hearing Loss (NIHL) a significant problem among manufacturing workers, reducing the noise form compressed air can be a simple solution and contribute toward reducing overall noise exposure levels. Many of these calls and emails revolve around reducing these exact noise levels, sometimes the open pipes have existing threads on them to install the solution immediately.
To reduce these noise levels, we need to simply reduce the amount of energy that is being expelled through the pipe. How do we do this you might ask? The use of an air nozzle will reduce the energy being dispersed from an open pipe. This will result in lower air consumption as well as lower sound levels while actually increasing velocity as the pipe will maintain higher operating pressures. Be cautious about the air nozzle you choose, however, they are not all created equal. EXAIR’s engineered air nozzles are among the quietest and most efficient air nozzles available.
What size pipes can we fit nozzles to? That’s a great question. We have nozzles that range from a 4mm straight thread all the way up to 1-1/4″ NPT thread. This also includes nearly any size in between especially the standard compressed air piping sizes. For instance, a 1/4″ Sched. 40 pipe that has 1/4″ MNPT threads on it can easily produce over a 100 dBA noise level from 3 feet away. This can easily be reduced to below 80 dBA from 3′ away by utilizing one of our model 1100 Super Air Nozzles. All it takes is a deep well socket and ratchet with some thread sealant.
This doesn’t just lower the sound level though, it reduces the amount of compressed air expelled through that open pipe by creating a restriction on the exit point. This permits the compressed air to reach a higher line pressure causing a higher exit velocity and due to the engineering within the nozzle, this will also eliminate dangerous dead-end pressure and complies with OSHA standard 29 CFR 1910.242(b).
All in all, a 30-second install can make an operator’s work station considerably quieter and potentially remove the need for hearing protection. If you would like to discuss how to lower noise levels in your facility, contact us.
One of the most common and dangerous hazards that occur within a manufacturing and production facility is the noise level within the plant. Noise is measured in units known as decibels. Decibels are a ratio of the power level of the sound compared to a logarithmic scale. If an employee is an exposed for too long to high levels of noise, they can begin to lose their hearing. That is where the OSHA 29 CFR 1910.95 regulation comes into play.
This OSHA standard doesn’t just provide the protection against noise in the work place but monitoring as well. Companies shall provide at no cost audiometric tests for all employees to ensure that no damage is being to the hearing of all personnel. This program is to be repeated every six months and the results are to be made accessible to all personnel.
Hearing is very important to our everyday lives and must be protected due to the fact that once it is damaged hearing loss cannot be lost be repaired. The OHSA 29 CFR 1910.95 is there to protect and monitor this dangerous hazard in the workplace so that all employees can go home safe and sound.
Here at EXAIR we design all of our products to safe and quite. Weather it is using one of our mufflers for vortex tubes or E-vac’s or one of our super air nozzles we strive to meet and exceed the OSHA standard. One could also purchase EXAIR’s Digital Sound Level Meter which can give a accurate and responsive reading of how loud your compressed air sources are.
For more information on EXAIR’s Digital Sound Level Meter and any of EXAIR‘s 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.
Cody Biehle Application Engineer EXAIR Corporation Visit us on the Web Follow me on Twitter Like us on Facebook
Sound levels and ROI don’t immediately link together in a quick thought. Unless you are me and things seem to link up that don’t always go together, like peanut butter and a cheese burger. (Trust me, just try it, or if you are near West Lafayette, Indiana just go try the Purvis Burger across the street from Purdue University.) The truth behind tying sound levels being reduced and ROI together is actually pretty simple.
For this example, I am going to stay fairly high level as we could get into some pretty deep measurements of what exactly could be a cost savings. If we reduce the sound level being generated by point of use compressed air products that is easiest to do by implementing engineered blow off products as well as reducing the operating pressure. Let’s use this example: A 1/4″ copper tube that is being used as a blow off will give off a noise level of over 100 dBA from 3′ away. The table below shows that at an 80 psig inlet pressure the same tube will also consume 33 SCFM of compressed air.
By installing a model 1100 1/4″ FNPT Super Air Nozzle on the end of this copper tube, we reduce the noise level generated by the blow off to 74 dBA. This measurement is at the same 80 psig inlet pressure and from 3′ away, which is well below the OSHA standard for allowable noise level exposure. This also gives a broader more defined pattern to the air stream which may permit a reduction in compressed air pressure.
The other factor this changes is that the air consumption is reduced by 19 SCFM of compressed air which then results in energy savings. This ultimately ends in a simple ROI equation where we are simply using the compressed air reduction as the only variable for the return.
By reducing the air consumption of a process that operates 24/7, 250 days a year that equates to a savings of 6,840,000 SCFM per year and that equates to $1,710.00 USD. This does not account for any reduction in paying for hearing protection that may no longer be needed, or increase in production because the application functions better.
So you see, reducing noise levels in a facility can easily amount to a sizable cost savings in energy going towards compressed air consumption. If you would like to walk through any potential applications, please contact us.
Over the years, EXAIR has come across a variety of different types of blow-off devices. We have seen copper tubes, pipes with a crushed end, fittings with holes drilled into them, and modular flex lines. For compressed air use, these are very dangerous and very inefficient. In many instances, companies will go through a mixed bag of items to make a blow-off device for their application. It is inexpensive to do. But what they do not realized is that these items are very unsafe and will waste your compressed air, costing you much money in the long run.
When EXAIR started to manufacture compressed air products in 1983, we created a culture in making high quality products that are safe, effective, and efficient. Since we stand by our products, we created a program called the Efficiency Lab. We test blow-off devices against EXAIR products in noise levels, flow usage, and force measurements. With calibrated test equipment, we compare the data in a detailed report for the customer to review. If we are less effective, we will state that in the report, but this is very rare. With this quantified information, we can then determine the total amount of air savings and safety improvements that EXAIR products can offer.
With our Efficiency Lab, it is quite simple to do. For starters, you can go to our Product Efficiency Survey on our website to give the conditions for testing. If you wish for a side by side analysis, you can place your pneumatic device in a box and send it to EXAIR. We will run the tests at the specified conditions or in a range of settings. We will then return your pneumatic device back to you with a report of the comparison. This report can be used to show managers, executives, HSE, etc. on the improvements that EXAIR can provide in cost savings and safety.
In a recent Efficiency Lab, a customer sent us a water jet nozzle that he was using to blow off product passing on a conveyor (reference photo above). The customer supplied us with the required information to test. They had three water jet nozzles on a manifold that had ¼” NPT male connections. The air pressure was set at 75 PSIG (5.2 bar), and the air pattern was round. Their annual usage for this blow-off device was 7000 hours continuous, and their electric rate for their facility was $0.10/KWh. The reason that they sent their nozzle to EXAIR was because the operation was very loud, and they believed that they were wasting compressed air. They asked me for a recommendation and what the payback period might be with my selection.
I recommended the model 1101 Super Air Nozzle as our standard round pattern with a ¼” NPT male connection. With our engineered design, the Super Air Nozzle can entrain the “free” ambient air into the air stream to generate a hard-hitting force; using less compressed air. Also, with this suggestion, they will not have to redesign their blow-off station; just remove the water jet nozzles and replace them with the Super Air Nozzles. We tested the water jet nozzle, and we found that it used 17.5 SCFM (496 SLPM) at 75 PSIG (5.2 bar). The noise level was measured at 91.2 dBA for a single nozzle. As a comparison, the model 1101 Super Air Nozzle will only use 13.3 SCFM (376 SLPM) of compressed air at 75 PSIG (5.2 bar); and, the noise level was reduced to 73 dBA for each nozzle.
The first thing that is important to me is safety. High noise levels will cause hearing damage. OSHA generated a standard 29CFR-1910.95a with a chart for Maximum Allowable Noise Exposure. To calculate the noise level for three nozzles, I will reference a previous blog that I wrote: “Measuring and Adding Sounds”. With three water jet nozzles, the total sound is 96 dBA. From the OSHA table above, the usage without hearing protection is less than 4 hours a day. With the Super Air Nozzles, the noise level will be 78 dBA for all three nozzles; well below the requirement for 8 hours of exposure. It is difficult to put a monetary value on safety, but using PPE should never be the first step as a solution.
For the annual savings and the payback period, I will only look at the electrical cost. (Since the Super Air Nozzle is using less compressed air, the maintenance and wear on your air compressor is reduced as well).
The air savings is calculated from the comparison; 17.5 SCFM – 13.3 SCFM = 4.2 SCFM per nozzle. With three nozzles, the total compressed air savings will be 12.6 SCFM for the blow-off station. An air compressor can produce 5.36 SCFM/KW of electricity at a cost of $0.10/KWh. For an annual savings, we have the figures from the information above; 7000 hours/year * 12.6 SCFM * $0.10/KWh * 1KW/5.36 SCFM = $1,645.52/year. For the payback period, the model 1101 Super Air Nozzle has a catalog price of $44.00 each, or $132.00 for three. The customer above did not disclose the cost of the water jet nozzles, but even at a zero value, the payback period will be just under 1 month. Wow!
Not all blow off devices are the same. With the customer above, they were able to reduce their noise levels and compressed air consumption. If your company decides to select an unconventional way to blow off parts without contacting EXAIR, there can be many hidden pitfalls; especially with safety. Besides, if you can save your company thousands of dollars per year as well, why go with a non-standard nozzle? If you have a blow off application and would like to compare it against an EXAIR product, you can discuss the details with an Application Engineer. What do you have to lose?