health & safety

---

 HEALTH & SAFETY ALERT The Crossrail Temporary Tunnel Ventilation System - TTVS What happened: The Temporary Tunnel Ventilation System (TTVS) is a Life Safety Critical system supporting the works within the trace. C610 have developed this H&S Alert for the TTVS and the importance of SSP Contracts working with Systemwide to ensure the System works correctly.

The above table shows maximum allowable pollutant concentrations

The level of ventilation required is governed by short-term (safety) and long-term (health) requirements to dilute pollutants to safe levels. Required Action: • Certain elements of C610 work require exclusion zones in sections of the tunnel. It is critical that these are observed as exposure to this air can place operatives at risk. • As the project progresses (particularly as hoardings come down) there will situations where Station Contracts will be working within their own demise, but will be exposed to “C610 air”.

Example of one of the Jet fans

• C610 will communicate any upcoming elements of work that could have an impact on Station Contracts ahead of commencement to ensure that correct measures are put in place. • Please also note, the TTVS is an interdependent system and can only work successfully when the exit routes for the air are kept to a minimum. It is critical therefore that hoarding doors between trackside areas and Stations are kept closed wherever possible . Example of a door wedged open allowing air into station

Date: 20 March 2017