At its meeting in Vancouver in 2010, International Tunnelling

Association Working Group 5 identified the need for guidance

on the use of high pressure compressed air. WG5 defined

this as “work in compressed air at pressures above historical

statutory limits, which in most countries are between 3 and 4

bar (gauge), and which involves the use of breathing mixtures

other than compressed natural air and can involve the use of

saturation techniques”.

High pressure compressed air working was a topic of interest

which had previously been addressed by the British Tunnelling

Society Compressed Air Working Group and which BTS CAWG

had identified as a significant development in the use of

hyperbaric techniques on site for which no guidance existed.

Consequently the ITA and BTS CAWG came together to jointly

publish the first edition of these guidelines in 2012 for use by

the international tunnelling community.

In 2013 a review and update of this document began, to take

account of the relatively rapid development of this technique.

That process has now been completed.

Comment and feedback continue to be welcomed and

should be made to the ITA Secretariat through the website

www/ita-aites.org.