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When equipment is rated as ATEX, what does this mean?


Hazardous Gas, Vapour and Mist Environments: ATEX Zones 1 and 2

ATEX is the name commonly given to the two European directives for controlling explosive atmospheres.

ATEX lifting equipment can mean electric chain hoists, wire rope hoists and belt hoists, winches, trolleys and pneumatic lifting equipment, and can be referred to as spark proof or Ex equipment.

1) Directive 99/92/EC (also known as ‘ATEX 137’ or the ‘ATEX Workplace Directive’) on minimum requirements for improving the health and safety protection of workers potentially at risk from explosive atmospheres.

2) Directive 94/9/EC (also known as ‘ATEX 95’ or ‘the ATEX Equipment Directive’) on the approximation of the laws of Members States concerning equipment and protective systems intended for use in potentially explosive atmospheres.

Hazardous Gas, Vapour and Mist Environments: ATEX Zones 1 and 2


Hazardous Dust Environments: ATEX Zones 21 and 22

A good example of an Zone 1 or Zone 2 classified operation would be a chemical or petrochemical plant, where there is a heightened risk for explosion during the course of normal day to day operations.

Within a hazardous gas environment an explosion can take place if a flammable substance, an oxidiser and a source of ignition are found simultaneously within the atmospheric air.

The absence of any one of these three elements would stop an explosion from occurring, and that is why through continued innovation and increased focus on safety the lifting equipment industry is able to offer a broad range of explosion proof and spark proof hoists, winches and trolleys, etc. specifically for safe use in these hazardous environments.

Zone 1 is an area that is classified ‘as a place in which an explosive atmosphere consisting of a mixture with air or flammable substances in the form of gas, vapours and mists is likely to occur occasionally during normal operation’, whereas Zone 2 is an area that is classified ‘as a place in which an explosive atmosphere consisting of a mixture with air or flammable substances in the form of gas, vapours and mists is not likely to occur in normal operation but if it does occur, it will be present for a short period of time only’.

Hazardous Dust Environments: ATEX Zones 21 and 22

ATEX Zones 21 and 22 are specific to hazardous dust environments, like can be found in the food industry in, for example, a flour mill where explosible dusts are often present.

Some examples of explosible dusts within the food industry alongside flour are custard powder, instant coffee, sugar, dried milk, potato powder and soup powder as a solid substance that is finely ground may ignite more readily or a lower energy.

The risk within the food industry with hazardous gas environments is that if any combustible substance is mixed or suspended in air at the correct concentrations and contained in a vessel or building when ignition occurs, then the result can be a violent explosion.

In a hazardous dust environment, an Zone 21 is classified as an area that is classified ‘as a place in which an explosive atmosphere in the form of a cloud of combustible dust in the air is likely to occur occasionally during normal operation’ whereas an Zone 22 is classified as ‘a place in which an explosive atmosphere in the form of a cloud of combustible dust in the air is not likely to occur in normal operation but if it does occur, it will be present for a short period of time only’.

Within any ATEX rated zone there is significant importance placed on safety and the necessity of spark proof/explosion proof hoists and lifting equipment is paramount.

vacuum classes

Vacuum Classes


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Hepa Filters

HEPA Filters – High efficiency particulate air (HEPA), originally called high-efficiency particulate absorber but also sometimes called high-efficiency particulate arresting or high-efficiency particulate arrestance, is a type of air filter. Filters meeting the HEPA standard have many applications, including use in medical facilities, automobiles, aircraft and homes. The filter must satisfy certain standards of efficiency such as those set by the United States Department of Energy (DOE).

To qualify as HEPA by most Western government standards, an air filter must remove (from the air that passes through) 99.97% of particles that have a size of 0.3 µm (micrometer).

HEPA was commercialized in the 1950s, and the original term became a registered trademark and later a generic term for highly efficient filters

HEPA is not just HEPA, HEPA is a classification that is widely used on filters for vacuum cleaners.

Our HEPA filters refer to the EN1822 (2009) standard

EPA 10 – EPA 12: Efficiency Particulate Air Filter

HEPA 13 – HEPA 14: High Efficiency Particulate Air Filter

ULPA 15 – ULPA 17: Ultra Low Penetration Air Filters

















An exception to the new standard applies to machines introduced into the market before 2010. These can use the old classification levels H10-H14. New machines introduced to the market in 2011 and later use the new classification levels E10-E12 and H13-H14. The outcome is that the H-level classification can only be used if the filter is H13 or H14, otherwise E-level classification E10-E12 is be used.

The HEPA classification of filters cannot be compared to the L, M, H and Type22 classification according to AS/NZ 60335.2.69. Therefore the HEPA classifications do not consider the suitability for use together with hazardous or combustible dusts, only the efficiency of filtration.

Superior Dust Control

Nearly a century of experience in high performance vacuum cleaners and filters means we can offer proven solutions that can help you create a cleaner and safer environment.

Our HEPA (High Efficiency Particle Air-filters) meter equipped dry vacs clean hotel rooms and patient wards efficiently. They also remove pathogenic dust from floor restoration processes. HEPA filters remove smoke, dust mite remains, pollen and bacteria HEPA Filtration means Dust Separation of 99.97% of particles down to 0.3 microns (one micron=millionth of a meter).




Understanding these terms is helpful when used with our Vacuumology article. They are presented in alphabetical order, except for a couple of very important ones at the beginning.

VACUUM (Water Lift) Inches of water lift. (Usually given at 0″ air opening). 

This explains the secret of the bowling ball trick. Direct all of a vacuum’s power onto one surface area and you can do amazing things. You have seen the commercials, right?

A vacuum’s ability to lift is a valid measurement. In fact, it is called vacuum, or waterlift. See how strong a vacuum can be created by slowing swallowing the air out of a plastic soda bottle. That is actually about all it takes to lift a bowling ball! But it takes more to vacuum a carpet.

If material is stuck in a vacuum pipe, suction is what jars objects loose. The suction capacity of a vacuum is not the key to effective vacuuming. The real key is how much air the vacuum is able to draw in (see CFM). Waterlift becomes more important when the air opening size is smaller – for example in air driven brushes.

CFM (Air Flow) Cubic Feet (of air) per Minute. (Usually give at 2″ air opening).

Wonder why that pebble won’t vacuum up but stays rattling in the end of your vacuum wand? Basically, without sufficient air moving around it, it’s going no where. Even a feather won’t budge without any air moving past it. Therefore, CFM (air flow) is so important for deep carpet cleaning. Some vacuums may be able to lift bowling balls, but the cleanest homes have central vacuums with tons of CFM. CFM becomes more important as the air opening size gets larger.


CFM = 13.35 d² (square root) VAC in H 2 O” 
Need: d – Diameter of orifice plate
vac – Inches of water lift

* Vacuum must be corrected before being put into equation. To correct, temperature and barometric pressure must be accounted for.


AIR PRESSURE – The air around us constantly exerts a pressure of about 400 inches of water. That means that every exposed surface has the equivalent of 400 inches of water pushing on the surface. A vacuum cleaner doesn’t actually create a vacuum, but it does lower air pressure inside the vacuum unit. Since the outside air is at normal pressure it rushes inward in a controlled airflow which creates the cleaning effect.

AIR WATTS: – “Cleanability Rating”

CFM x VACUUM (Water Lift) 

Note: Both the CFM and the Water-lift must be measured at the same air opening size. 

AMPS – Current draw of the motor. Amperage current draw of electricity required to operate the vacuum motor. A motor that uses more electrical current does not always mean the current is being used more efficiently.

ARMATURE – The center part of the motor which rotates making the transfer of electricity across the motor, enabling the motor shaft to spin. A quality armature is mounted on ball bearings, and protected from incoming vacuum air that has been heated and dirtied.

BYPASS COOLING – A separate stream of air that cools the motor, different from the air that draws in dirt from the home. Air being vacuumed does not actually flow through the electrical components of the motor. Normally these motors have a separate fan to provide cooling air to the motor.

CYCLONIC ACTION – Cyclonic action describes the natural action found in a tornado. In a vacuum with cyclonic filtration, the air carrying the dust and debris moves through a tornado action. The air swirls downward in a cone-shaped pattern. At the bottom of the cone, it starts swirling upward again, inside the downward cone. Thus this is sometimes called a “reverse” tornado action or “dual cyclonic action”. The vast majority of the debris separates from the air stream as air reaches the bottom of the swirl, and is deposited in the dirt container. A fraction of the debris remains in the air, to be removed by the secondary filter, if any secondary filters exist.

FAN (and fan stages) – The fan is the combination of blades that spin around to create the airflow to produce the vacuuming action. Fans are flat impellors, and are combined in a set of two or three fans on each motor, depending on the model. A motor with two fans is called “two-stage”; if it has three fans its “three-stage”. Each fan – set of blades – increases the sealed vacuum, or maximum air pressure drawn through the system. Additional sets of fans will change the air flow dynamics, adding fans will increase water-lift and decrease CFM. Air driven power brushes work better with a motor with more fan stages, whereas electric brushes operate better with less fan stages.

HEPA – HEPA stands for High Efficiency Particle Arrestor, used to reduce the number of contaminants in indoor air. A HEPA filter will arrest or stop 99.97% of all particles .3 microns or larger. HEPA filters – used in “clean rooms” – are essential in medicine and in the manufacture of computer components. However, they have limitations in vacuums. They tend to leak in vacuums, because they were never intended to be used as small, portable filters. They are expensive and must be discarded because they cannot be cleaned. They clog quickly and strangle airflow. And even when working perfectly, up to half the respirable particles in indoor air are small enough to go right through a HEPA filter. Very, very few vacuums are truly “HEPA” certified but many only use filter material which is “HEPA” level. M.D. offers bags for their systems that meet these filter material specifications.

a) Peak Horsepower (PHP): Maximum instantaneous horsepower capability of a 
Motor. ( most frequently used but very deceptive)
b) Input HP: Maximum watts divided by 746.
c) Operating HP: Watts at operating point divided by 746.

MAXIMUM AIR WATTS – This is recognized by the American Society of Testing and Materials (ASTM) as the best way to measure the actual cleaning power of a vacuum system. Most manufactures provide statistics for the maximum air watts that may not be the actual amount produced under the conditions most often used. Make sure you know the opening size of the attachment most often used and then find the vacuum’s air watts at that exact opening size. Read our vacuumology article.

MOTOR SPEED – Measured in revolutions per minute (RPM). Higher RPM motors may not last as long.

OVERALL EFFICIENCY – “Measure of Fan Efficiency”


ORIFICE (Air Opening) – Simulation of restrictions (impedance) in a cleaner system.

OPERATING ORIFICE – Restriction typical of operating conditions.

PAPER BAG – A collection device for dust and debris used by some vacuum cleaner manufacturers. Paper bags are a definitely the cleaner home owner’s choice.

POWER NOZZLE – These are designed to loosen stubborn dirt in carpets, and make it available for removal by the air flow. M.D. power nozzles are optimally designed to remove both common kinds of carpet dirt; our dual soft bristles gently free debris that naturally sticks to carpet surfaces; threads, lint, pet hairs, etc. And our beater brush agitates and vibrates carpet, to loosen the sand-like grit down between carpet fibers.

PVC (Poly Vinyl Chloride) – A common plastic polymer that provides excellent appearance and longevity with good flame retardance at an affordable price. All of M.D. Manufacturing central vacuum fittings – renowned for their quality in the vacuum industry – are made from PVC.

RESTRICTIONS – Hose, wands, filters, carpet, water, foam, voltage fluctuation (anything which impedes airflow)

SEALED BEARINGS – Often used in high quality motors to prevent dust and debris from entering the motor bearing area. All M.D. motors have sealed bearings.

SEALED VACUUM GAUGE – Is a device to measure maximum vacuum or water lift by sealing off the vacuum intake port. It measures in “Inches of Water-lift”. This is not for picking up water but a means of comparing lifting abilities of a solid column of water.

SOFT START – The electronic means of slowly starting vacuum motors to reduce initial in-rush voltage spikes. It starts the motor at a slower voltage, slowly ramping up to operation voltage. No tests by Ametek or any other agency have ever produced any quantifiable measurement of this extending any motor’s life. It does however; allow the manufacturer to utilize a smaller capacity of relay which is less expensive.

STANDARD CONDITIONS – 120 volts, 60 Hz., corrected to standard conditions of 29.92 barometric pressure and 68º F.

STAGES – See Fan Stages.

THRU-FLOW MOTOR – In some less-expensive motors, the air drawn from the home flows right through the motor to cool it. Unfortunately this air is laden with the dust from the home which dirties and contaminates the motor. This air is also warmed by friction as it moves through hoses and piping, and is substantially warmer so it is less able to cool the motor. Thru-flow motors will overheat if they are run for long periods of time without adequate air flowing through the system.

VOLTAGE (Volts) – A measure of the electrical potential employed by a vacuum motor. Typically, motors require common household current; 110-120 volts in North America; 240 volts in other parts of the world. Voltage is to electricity as pressure is to water, a measure of potential or driving force.

WATTS – Electrical power consumption of the motor.

WATERLIFT – See Vacuum (first definition)


Feel free to give us a ring today for additional information and advice.

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