Recent legislation has demanded the use of Air Handling Equipment when stripping asbestos. The primary reasons for ventilation are:

• To create a pressure differential between the enclosure where asbestos is to be removed and the clean area surrounding it. This is usually referred to as “NEGATIVE PRESSUREâ€Â� and its purpose is to contain any airborne dust within the enclosure.
• To provide a movement of air “AIR CHANGESâ€Â� to enable airborne dust to be entrapped within the high efficiency filters which the ventilation equipment must include.

The new CMXe Pressure Differential Monitor/ Recorder by Torchcross can be used for proving efficiency in enclosures and containments used for:

• Asbestos Removal and Treatment;
• Nuclear Dismantling;
• Handling of bacteriological and chemical agents;
• Clean rooms; and
• Decontamination facilities.

It is one of the most complete containment management systems available today. It has a large, high visibility, LCD display which shows any alarm condition and a graphical representation of the pressure against time. The display can also used in the setting up of alarm points and external devices.

It also records all readings during a contract period onto a SD card, which can be connected to a computer and downloaded into Torchcross software to provide graphs and reports of all monitored events. The card will hold large amounts of data, enough for the longest contract. The information can then be printed and/or recorded to a CD to be kept for long periods of time in order to provide data for evidential or insurance company purposes.

The monitor is set up by recording all parameters onto the SD card. These include company name, job details, high and low pressure settings. There is also an optional GSM unit which if installed, can be programmed for up to 3 fixed dial telephone numbers when the job is set up. This unit will then send a SMS message to the appropriate person should an alarm condition occur. This means sites which are unmanned during evenings or weekends will still be controlled.

The pressure differential monitor/recorder has:

• Two zero voltage output sockets to feed an external alarm klaxon, flashing beacon and standby air moving unit via a suitable relay. A loud onboard audible alarm is built in.
• A self seeking power supply for use at any voltage from 110v to 240v ac.
• Battery backup which provides hours of operation if power supply is interrupted.
• An onboard real-time clock that gives accurate time and date recording.

For an example of how the monitor/recorder is used, please see the figure below.

 

 

THE WORKING AREA ILLUSTRATION

Prior to commencement of work, the area where asbestos is to be removed is sealed off using polythene sheeting and made as air tight as possible. Site conditions usually render it impossible to obtain a seal which is 100% airtight and a certain degree of leakage is always evident. A controlled access device (also known as a decontamination unit) is sealed to the working area to allow operatives to pass through “AIRLOCKS� to prevent escape of dust during entry and exit. A separate Code of Practice exits detailing the correct procedures for carrying out this operation. A device must then be attached to the installation, capable of extracting air from the working area and passing the air through high efficiency filters to entrap any harmful fibres. The type and size of the device “AIR MOVER� varies according to the installation.These are usually called negative air units or negative pressure units.

On the 15 of February 2010 Safe Work Australia (SWA) released a report titled “Asbestos Exposure and Compliance Study of Construction and Maintenance Workers“.

It found that most tradesmen were generally aware of the potential hazards and health risks of asbestos. However the level of general awareness was not accompanied by the knowledge of how to recognise asbestos or control the risks when working with it. Their practical ability to reliably identify asbestos hazards was limited.  This was generally because their identification skills were insufficient, asbestos registers were often absent or inaccurate and few premises had labelling of materials or areas containing asbestos. For more information and to read the report click on the link above.