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Breathe in complete safety
Many hazardous industrial environments require personnel to wear breathing air masks or suits for protection, relying totally for their security on the connection to the breathing air circuit. Craig Forrester, Stäubli Connectors UK Manager, reviews some of the life threatening hazards that can potentially arise during use and how these can be eliminated.
What are the main factors to consider when using a breathing air circuit?
Breathing air lines have to perform perfectly with total reliability. Any chance of accidental disconnection or connection to the wrong circuit must be avoided. Dangerous incidents resulting from accidental disconnection or connecting to unsuitable gases still occur. The cause of most accidents could be avoided by using connectors specifically designed for the job and not an adaptation of standard compressed air connectors. Breathing air connectors should be readily identifiable, require at least two distinct and separate actions to disconnect and be incapable of connection to any other circuits. Otherwise it has been said that breathing air connectors are accidents waiting to happen.
What safeguards can ensure connection is only made to the correct circuit?
Many factory environments contain circuits for compressed air, gases and fluids frequently positioned alongside a dedicated breathing air circuit. Breathing air lines tend to be used only infrequently and are often located in less prominent locations. Accidental connection of the breathing air circuit to unfiltered compressed air or other gases is a real danger. Identification is commonly assisted by use of a distinct colour code for the breathing air circuit. Much better than a colour code is a unique plug profile that will mechanically only allow connection to the correct circuit eliminating any possibility of making a wrong connection.
How can the dedicated breathing air circuit be immediately recognised?
By distinctive colour coding of the circuit making it stand out clearly from the other circuits and connectors in the vicinity. Stäubli standardised on blue for all their breathing air connectors and associated breathing air equipment. Identification in the stores is equally important to ensure the correct item is selected for use on the breathing air circuits.
Can accidental disconnection be avoided?
A safe breathing air connector should require at least two deliberate and separate actions to disconnect. Stäubli's design is a connector plug which has to be pushed into the socket and then by pressing on the release button the coupling will safely disconnect. This conforms precisely to the safety requirements of the latest BS EN 139 Standard. Additional security against disconnection can be provided by padlocking the connector, a useful precaution where personnel using breathing air may be out of sight of the source.
Which air circuits can be used for breathing air?
Standard compressed air lines are unsuitable directly for breathing air usage. The air first needs to be filtered and pre-dried to at least instrument air quality. Instrument air can be used for breathing with the use of a second filter. A two-stage additional filtration is recommended by Stäubli with the first stage sub-micronic filter eliminating any solid particles or aerosols and the second stage activated carbon filter for absorption of any oil vapour, aerosols and odour.
Typically up to 4 breathing air lines or masks can be connected to a portable filter unit with an inbuilt manifold, such as Stäubli's BQR, which in turn is connected to an instrument air supply.
How is the requirement for additional breathing air lines accommodated?
When a number of suits or masks need to be supplied directly from a dedicated breathing air circuit, a portable manifold unit eliminates the need to run separate lines back to the source. Stäubli's manifold is capable of connecting 6 masks or half suits or 4 ventilated suits and is fitted with their safety connectors having the unique plug profile to ensure that connection can only be made to the correct circuit.
What would be your advice to companies installing breathing air circuits?
Determine requirements at the initial design stage and do not compromise on the installation. Frequently in the development of the workplace environment the need for breathing air circuits is addressed late in the project after many crucial decisions have already been made that could affect the breathing air installation. Select products that have been specifically designed for breathing air applications not those adapted from standard compressed air designs.
How can Stäubli Connectors help?
Stäubli's range of products has been specifically designed for breathing air applications and has been fully tested in use. The plug profile is unique and not an adaptation of standard compressed air designs. The range includes all the elements needed to create and support breathing air circuits in industrial environments. Their design introduces several innovative safety features to ensure reliable operation and eliminate any risk of wrong connection or unintentional disconnection.
Experienced Stäubli engineers are available to make recommendations on the equipment required for any breathing air application.
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