A confined space is a closed or partially closed structure and most of severe or lethal accidents that occur while entering these areas are linked to combustible, toxic or asphyxiating (lack of oxygen) gases. Ce seront donc les premiers risques à évaluer dans le cadre de l’élaboration d’une procédure de travail avec des appareils de détection de gaz dans les tunnels.
GAS EXPOSURE IN TUNNELS
Chronic exposure to exhaust gases can cause severe neurological disorders (headaches, dizziness, irritability, drowsiness, convulsions), bronchial irritations or even lungs cancer in some cases. It is thus essential to permanently measure and control TWA (time weighted average) and STEL (short term exposure limit) exposure values in road and railroad tunnels for:
- Carbon monoxide
- Carbon dioxide
- Nitrogen oxides (nitric oxide and nitrogen dioxide)
- Sulphur dioxide
- Volatile organic compounds (VOC) including benzene
- Oxygen defficiency
GAS DETECTION FOR TUNNELS
Multigas detector and area gas monitor
Concerning personal protection, a multigas detector remains essential and indispensable. In addition, a gas area monitor will secure the working area. For very long tunnels, it will be advisable to use units with communication solutions as explained below…
LENS Wireless technology
Particularly suitable for tunnels, the LENS™ Wireless technology is a new way to approach safety. With this technology, once a detector or an area gas monitor enters in alarm following a gas hazard, a « man in distress » alarm or a panic situation, every paired detector will get instant alert.
respiratory protection and self-rescuer mask
Self-rescuer masks a respiratory protective devices especially designed for emergency evacuation in non-breathable atmosphere – poorly oxygenated, smoky or extremmely toxic areas – for use when an air purifying respirator would be unefficient or hazardous. They originally have been designed for emergency evacuations from mines or long tunnels.