What is Sound: The Correlation Between Sound Power and Sound Pressure

Sound, it is all around at every given point of the day. Whether it is from the music we listen to, the person talking to you, your cars engine, or the wind blowing through the leaves there is no escaping it. Hearing is one of the five senses that the majority of humans rely on and should be protected at all costs and with a good understanding of what sound is, one can help mitigate damage done to their hearing. Sound can be broken down into two parts, sound power and sound pressure. But the real question is, how do these corollate to each other to become the sound that we rely on.

Sound Wave

Sound Power (Watts) is defined as the rate at which sound energy (decibels) is emitted, reflected, transmitted or received, per unit of time. Whereas, Sound Pressure is defined as the local pressure deviation from the ambient atmospheric pressure, caused by a sound wave. Based on these two definitions it can be determined that sound power is the cause that generates the sound wave and sound pressure is the effect or what we hear after the sound wave has traveled to the ear.

This can be summed up in a simple analogy using a light bulb. Light bulbs use electricity to generate a source of light, this means that the power required (also stated in Watts) to cause the bulb to light up is comparable to Sound Power. The intensity of the light being generated (stated in Lumens) would be the Sound Pressure. Sound Pressure is what we would typically hear or call sound. This is what is measured because that is the harmful aspect to our hearing and ears. If the Sound Pressure is high enough and the ear is exposed to it long enough, permanent damage can be done resulting in hearing loss to the point of complete hearing lose.

I have known many people who have lost there hearing either completely or a large portion of it from exposure to loud noises. EXAIR designs and manufactures quiet and efficient point of use compressed air products. These products either meet or exceed the OSHA noise Standards in OSHA Standard 29 CFR – 1910.95 (a).

The OSHA Standard for how long someone can be exposed to a certain noise level

If you are not sure what the noise level is in your facility check out EXAIR’s Digital Sound Level Meter. It’s an easy to use instrument for measuring Sound Pressure levels in an area.

EXAIR’s Digital Sound Level Meter

If you have questions about the Digital Sound Level Meter, or would like to talk about any of the quiet EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR or any Application Engineer.

Cody Biehle
Application Engineer
EXAIR Corporation
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EXAIR Supports your ROI Efforts

EXAIR not only has products that will reduce your air consumption, cost and noise levels but also has the tools to help you calculate the annual savings and Return on Investment (ROI). Sometimes you have the materials in house to make your own pneumatic tools so you get that piece of pipe in the maintenance crib, drill several holes and connect your compressed air. It works, your team is proud of the solution and everyone moves on to the next fire, right?

Several projects later you notice that your compressed air usage seems very high so a team is assembled and challenged with a cost savings program geared towards compressed air savings. EXAIR is the company that can help. We have Intelligent Compressed Air Products, Free Expert Technical Help and savings calculators that can be used to show the savings in your reports and presentations. EXAIR’s cost savings calculator will simplify the savings for each process you study and help your efforts in purchase justifications.

We have several examples of helping our customers save money such as this blog by one of our talented Application Engineers. You will realize more than cost savings as you should also see significant sound reductions and safety improvements as all of our products meet or exceed OSHA standard 29 CFR 1910.95 (a) which outlines allowable noise exposure for personnel and OSHA standard 29 CFR1910.242 (b) Dead End Pressure requirements.

When you begin compressed air cost savings program and have questions as to where to start, how to calculate and how to prepare your justifications please give EXAIR a call and talk with one of our many talented Application Engineers. EXAIR’s Intelligent Compressed Air products and Application Engineers will support all your efforts to decrease compressed air usage, reduce sound levels and increase the safety of your environment.

Eric Kuhnash
Application Engineer
E-mail: EricKuhnash@exair.com
Twitter: Twitter: @EXAIR_EK

EXAIR Product Overview: Mufflers

Noise, we all hate it to some extent. From the hustle and bustle of crowed streets to the whine of a jet engine noise has plagued the world for eons leaving people to search for a way to escape into a moment of peace and quiet. The majority of people that I know pack their massive over sized backpacks and head deep into the mountains for days on end to escape the noise sometimes traveling for 10+ miles at a time. But how can we help eliminate this monstrosity that we have created in our manufacturing environments? The answer is mufflers, and no I don’t mean your car muffler (although they do the same thing) I mean compressed air mufflers. Compressed air can be a loud utility inside of a plant environment and exceed the OSHA guidelines for personnel noise exposure. But this noise can easily be mitigated with the use of Intelligent compressed air products and mufflers.

Big Sandy Lake Trail – Wind River Range State Park, WY

OSHA Standard 29 CFR 1910.95(a) outlines the total noise exposure to a particular noise level per day and dictates that noise exposure at or above 85 decibels require ear protection. By placing a muffler on the end of the pipe one can reduce the sound level significantly to the point it could be the difference between having to wear ear protection and not having to. With that being said EXAIR offers four different types of mufflers to choose from and they are Reclassifying, Sintered Bronze, Straight-Through, and Heavy Duty.

Reclassifying mufflers offer the best noise reduction at 35 dB and have the added benefit of removing oil mist from the air line. This means that the Reclassifying mufflers are ideal for pneumatic cylinders. Per OSHA Standard 29 CFR 1910.1000 worker shall not be exposed to more than 5mg/m3 of oil by volume in a 40-hour work week. The patented design of the removable element separates oil from the exhausted air and meets or exceeds the OSHA Standard.

Sintered Bronze Mufflers are an excellent low-cost solution which can be easily installed into your current existing ports. These mufflers also come in the largest variety of different sizes ranging from thread sizes of #10-32 to 1.5” NPT. Also, the Sintered Bronze Mufflers are specifically designed to provide the minimal amount of back pressure and restriction. The main difference between these mufflers and the reclassifying is that the Sintered Bronze Mufflers cannot collect oil out of the exhaust.

The quick pick chart for easily choosing which muffler you need

If the process air needs to be directly plumbed away from personnel, then the Straight-Through Muffler is the way to go. Straight-Through Mufflers are ideal for situations that require both a threaded inlet and exhaust. In most applications you will see the Straight-Through Muffler pair with our E-Vac vacuum generators or Vortex Tubes to provide noise reduction of the unit. All in all, the Straight-Through Muffler can reduce noise levels up to 20 dB.

Model 3913 Straight-Through Muffler

Lastly, the Heavy Duty Muffler provides a corrosion resistant aluminum outer shell with a stainless steel inner screen. This design allows the muffler to catch any contaminants such as rust from being ejected potentially causing harm or quality defects. Typically, this muffle will reduce noise levels up to 14 dB.

Model 3903 Heavy Duty Muffler

If you have any questions or want more information on EXAIR’s E-Vacs and their Accessories. Give us a call, we have a team of application engineers ready to answer your questions and recommend a solution for your applications.

Cody Biehle
Application Engineer
EXAIR Corporation
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Save Your Compressed Air Today with These Simple Methods

When discussing ROI, return on investment, for an industrial compressed air system it is necessary to  understand what it costs to produce compressed air.  Generally we calculate that it costs .25 cents to produce 1,000 SCF (Standard Cubic Feet) of compressed air here in the Midwest of the United States. For our example let’s consider a typical 250 HP industrial compressor running 24 hours per day/5 days per week for 52 weeks.  This compressor can generate 374,400,000 SCF per year, using the industry standard utility cost for the Midwest of .25 cents per 1,000 SCF it will cost $93,600 to produce that volume of compressed air.

To avoid wasting money on compressed air generation it is extremely important to eliminate unintended or wasteful compressed air use in your plant. The two main offenders are leaks and open tube blow-offs.  While soapy water is a good method for discovering leaks, EXAIR offers the Ultrasonic Leak Detector.  This handy device allows leaks to be detected at distances of up to 20′ away! Also consider how safe and convenient it is to find leaks in overhead pipes while standing on the ground instead of on a ladder. Using a tool like this to do an entire system leak audit can easily result in many small leaks being identified and when fixed result in a large savings.

open tubes
Thirteen Open Tube Blow-Offs

Now let’s look at what an open pipe or tube may consume. A single 1/4″ OD copper tube can use 33 SCFM @ 80 PSIG inlet pressure.  Using the manifold pictured above as our example with 13 open tubes, each tube can consume 33 SCFM @ 80 PSI inlet pressure. With 13 open tubes running 24 hours a day, 5 days a week, 52 weeks per year equates to a total consumption of  160,617,600 SCF annually.  If we installed the EXAIR model 1100 Super Air Nozzle  using a simple compression fitting we would reduce the air consumption dramatically.  The EXAIR 1100 Super Air Nozzle consumes 14 SCFM @ 80 PSIG inlet pressure, running 24 hours a day, 5 days a week, 52 weeks per year equates to a total consumption of 68,140,800 SCF annually.  That change will save you 92,476,800 SCF annually which is equal to $23,119.20 and 24.7% of air compressor capacity!  These calculations are all based on continuous running applications, if intermittent operation is possible consider the EXAIR Electronic Flow Control for even greater savings.  The EXAIR Electronic Flow Control combines a photoelectric sensor with timing control that limits compressed air use by turning it off when no part is present

Open pipe blow offs also violate OSHA standard 29 CFR 1910.242(b) requirement for using compressed air for cleaning when pressurized above 30 PSIG. Not to mention they generally are louder than 90 dBA, which is the maximum allowable noise exposure without hearing protection under OSHA standard 29 CFR – 1910.95 (a). The EXAIR engineered Super Air Nozzle is a great way to avoid a OSHA fine.

A great product that will help you keep your fingers on the pulse of compressed air consumption and demand is by incorporating the EXAIR Digital Flow Meter.  This handy item mounts directly to the pipe.  The digital display shows the amount of compressed air being used in any leg of your distribution system.  The Digital Flow Meter is offered in sizes for 1/2″ – 4″ Schedule 40 Iron Pipe and 3/4″ – 4″ Copper Pipe.  It also is available with the Summing Remote Display that is prewired with a 50′ cable, it is powered by the Digital Flow Meter and with a push of the button will display either the current compressed air consumption, consumption for the previous 24 hours or the total cumulative usage.

The Digital Flowmeters are also available with wireless capability using the ZigBee mesh network protocol, data can be passed from meter to meter to extend the distance over which the wireless system can operate.  Each meter has a range of up to 100′ (30 meters). Or you can opt for the USB Data Logger option.  The USB Data Logger can store approximately 9 hours of readings if set to sample once every second or up to 2 years if sampled every 12 hours.

If you would like to talk about any of the quiet EXAIR Intelligent Compressed Air® products or our line of Optimization Products, feel free to contact me or any EXAIR  Application Engineer.

Russ Bowman, CCASS

Application Engineer
EXAIR Corporation
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