عدد المساهمات : 16359
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تاريخ التسجيل : 01/07/2009
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العمل : مدير منتدى هندسة الإنتاج والتصميم الميكانيكى
الجامعة : المنوفية
|موضوع: كتيب بعنوان Understanding Compressed Air Safety and Savings السبت 10 أكتوبر 2020, 1:28 am|| |
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أحضرت لكم كتيب بعنوان
Understanding Compressed Air Safety and Savings
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Why is compressed air safety a concern?
Compressed air is commonly referred to as the “fourth utility” because it is
very common as a resource within manufacturing, mining and processing
environments. Employees or contractors
in every industrial company or setting are
exposed to compressed air’s effects
regularly and it should be handled with
responsibility and care. The primary
dangers from compressed air come
from high pressure and noise exposure.
Personnel being exposed to compressed air which exits an open line or
non-safety nozzle at a higher pressure than 30 PSI risk the air entering
the bloodstream and causing air embolism, a serious health risk.
Improper use of compressed air commonly exceeds OSHA’s noise
exposure standards and causes noise induced hearing loss (NIHL). The
CDC reports NIHL is one of the most common
occupational diseases and the second most
self-reported occupational illness or injury.
According to the National Association of
Manufacturing, there are 12.3 million people
working in the manufacturing sector, which
accounts for approximately 9% of the U.S.
workforce. According to the Bureau of
Labor Statistics, occupational hearing loss
is the most commonly recordable occupational illness in manufacturing
accounting for 1 in 9 recorded illnesses. More than 72% of these occur
among workers in manufacturing.
Are there regulations that govern the use
of compressed air?
Yes, OSHA has two important standards relevant to compressed air.
Standard 29 CFR 1910.242(b) is specific to compressed air use for cleaning
and states – “Compressed air shall not be used for cleaning purposes
except where reduced to less than 30 p.s.i. and then only with effective
hearing loss is the most
and noise is effectively
done by using products
which are purposefully
designed to meet these
strict OSHA safety
Air Safety and Savings02
chip guarding and personal protective equipment.” OSHA’s own interpretation goes on to state, “the downstream pressure of the air at the nozzle
(nozzle pressure) or opening of a gun, pipe, cleaning lance, etc., used for
cleaning purposes will remain at a pressure level below 30 psi for all static
conditions. The requirements for dynamic flow are such that in the case
when blockage of the air exit (dead-ending) occurs a static pressure at the
main orifice shall not exceed 30 psi”.
And because compressed air can be loud and result in hearing loss when it
is used through poor nozzles, open tubes and pipe, or home-made blowoffs,
their noise exposure standard is important. This standard 29 CFR 1910.95(a)
outlines the allowable time a person can be exposed to a specific decibel
level as follows:
Limiting pressure and noise is effectively done by using products which are
purposefully designed to meet these strict OSHA safety standards. There are
many different options for using compressed air within a machine or out on
the plant floor but many of them do not take these two important OSHA
standards into account. Engineered compressed air products, made for
end use compressed air applications, should possess the ability to prevent
blockage of the compressed air orifice and keep noise below allowable
thresholds. Products to consider are engineered air nozzles, air knives, air
amplifiers and safety air guns which are outfitted with an OSHA compliant
nozzle. Acceptable air nozzles and other end-use products are designed
to prevent blocking of the outlet orifice. They are also manufactured with
precision to create a non-turbulent airflow which keeps noise to a minimum.
OSHA Maximum Allowable Noise Exposure
Hours per day (constant noise) 8 7 4 3 2 1 0.5
Sound level dBA 90 91 95 97 100 105 110
OSHA Standard 29 CFR - 1910.95(a)
Air Safety and Savings03
How can engineers effectively
limit pressure and noise?
By following the CDC’s Hierarchy of Controls, engineers can eliminate loud
and unsafe pressure nozzles by first designing with quiet and pressure safe
engineered compressed air products like air nozzles, air knives and air amplifiers.
Engineers should also take steps to replace existing products with 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 because they
are typically permanent installations and can be achieved with little effort.
It can be as simple as adding these products to an existing drawing or adding
a compression fitting to an open tube and screwing in a nozzle. Isolating
people from the hazard is not always possible in the complex setup of a
manufacturing plant. Changing the way people go about doing their job
is also a long and complicated process. Personal Protective Equipment (PPE)
is too often discarded, modified or forgotten.
How do engineered air nozzles work?
Air Nozzles use the Coanda effect to amplify compressed airflow up to 25 times or more.
As illustrated on the right, compressed air (black arrows) is ejected through a series of
nozzles on the outer perimeter. As the air travels along the outer wall of the nozzle,
surrounding air (blue arrows) is entrained into the stream. The
airstream that results is a high volume, high velocity blast of
air at minimal consumption. The air is always ejected so
it can vent safely, well below OSHA dead end pressure
requirements, should the nozzle end be blocked.
Air Safety and Savings
Hierarchy of Controls
Physically remove the hazard by designing in
low noise and low outlet pressure products
Replace the existing hazard with low
noise and low outlet pressure products
Isolate people from the hazard
Change the way people work
Provide the worker with personal
Super Air Amplifiers
Do they come in different versions?
Engineered compressed air nozzles come in many shapes and sizes, as
well as materials. Manufacturers generally separate them by their force
values with product lines containing standard force air nozzles and high
force air nozzles. Force is also directly related to air use,
the more high energy compressed air a nozzle, uses
the more force it produces and the more work it
can get done. The material of construction makes a
significant difference in where the nozzle should
be used. Zinc/Aluminum and Brass material
is good for general industrial use without
the presence of corrosives or extreme
temperatures. Stainless steel material
will combat corrosion and high
temperatures. PEEK thermoplastic
and PVDF plastic materials combat
chemical environments and also have good temperature ratings. These
plastics are also non-marring which makes them good for applications with
sensitive surfaces or finishes.
Are there similar, related products?
Yes, related products which possess the OSHA compliant qualities of
eliminating dead-end pressure and reducing noise levels include: Air Knives,
which produce a laminar sheet of air over a wide area used for cooling, cleaning,
drying and blowoff. Air Amplifiers use the Coanda effect to amplify the
volume of total air flow delivered to a surface or process. They are very good
at venting and exhausting fumes, cooling and drying. Air Wipes provide a
360° blowoff and are used to clean or cool wire, cable, and extruded profiles.
The best safety air guns are outfitted with engineered air nozzles so that they
possess the same qualities as the nozzles.
Super Air Nozzles
Air Safety and Savings
Super Air Knives Super Air Wipes
Select from the
products on the
right to learn
Safety Air Guns
Click Here to Request
EXAIR's Newest Catalog!05
Money Savings Potential
The other benefit that an engineered compressed air solution provides is
the ability to use less of your compressed air. These products are designed to
operate as efficiently as possible and reduce the use of costly compressed air.
Designing machines and processes, which require compressed air, with
engineered compressed air products will result in the most efficient use
of air. Retrofitting processes and machines with engineered products can
reduce the cost of manufacturing and provide a very quick return-oninvestment from the compressed air savings.
A major North American Bakery has been working on specific legs, one at
a time, of their production process to reduce compressed air consumption
throughout their plant. This specific example used a home-made compressed
air nozzle to de-pan rolls from their baking pans.
They had fabricated their own nozzle by capping off a 3/8" pipe and drilling
a 9/64" hole in the cap. Running at 80 PSIG this “nozzle” consumed 25.4 SCFM.
When retrofitting the pipe to use an engineered air nozzle the result was 17
SCFM at 80 PSIG, clear savings of 8.4 SCFM. There were ten nozzles used for
removing rolls from the pans and it was a two shift per day operation. The
following savings calculation is for one production line, in many facilities
there will be more, and more opportunities for savings on additional lines.
• Savings = 8.4 SCFM per nozzle (ten total)
8.4 x 10 = 84 SCFM total
• Two Shifts per day = 960 minutes
250 working days per year = 240,000 minutes
• Yearly Air Savings = 20,160,000 ft3 saved
Using the average compressed air cost of $0.25/1,000 ft3 we can
further quantify the savings.
• 20,160,000 ft3/1,000 = 20,160
20,160 x $0.25 = $5,040.00 total savings per year
The total investment for the engineered compressed air nozzles
(EXAIR model #1100) was $360.00, for a simple ROI of 26 days.
The force value of the home-made “nozzle” was 1.04 pounds at 80 PSIG.
The air amplification characteristic of the engineered air nozzle allowed
for a significant reduction in compressed air consumption while still
being able to maintain a force value of 1 pound at 80 PSIG inlet.
Air Safety and Savings06
What are some typical applications that
use these types of products?
As previously mentioned these products excel at using compressed air
safely and efficiently for applications such as blowoff, cleaning, drying,
cooling, ventilating, circulating, part ejection, part manipulation and
EXAIR has a staff of application engineers ready to assist
you in selecting the appropriate model for your application.
They can be contacted at 1-800-903-9247.
Or you can email them at email@example.com 11510 Goldcoast Drive Phone (800) 903-9247 ..FAX (513) 671-3363 Cincinnati, Ohio 45249-1621 . E-mail: Techelp@exair.com
Manufacturing Intelligent Compressed Air Products Since 1983
Select from the products below to learn more
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