What is BS EN 12110 - tunnelling machine airlocks about?  
Tunnelling machines excavate tunnels with a circular cross section through a variety of soil and rock strata. Airlocks are vital components for the smooth functioning of tunnelling machines. BS EN 12110 is a European Standard that discusses the safety requirements of airlocks for tunnelling machines.
BS EN 12110 applies to the design, construction, equipping, marking, and testing of airlocks as defined in 3.3 including pressure bulkheads as defined in 3.4, which are to be used in tunnelling work. An oxygen-breathing system used to provide the breathing supply necessary to conduct a safe decompression is also covered by BS EN 12110.
Note 1: BS EN 12110 is not applicable to machinery and equipment which is manufactured before the date of publication of BS EN 12110 by CEN.
Note 2: BS EN 12110 does not cover the supply of services to the airlock.
Note 3: Vibration, noise, and EMC (Electromagnetic compatibility) hazards are not significant hazards for airlocks.
Note 4: BS EN 12110 does not cover the hazards due to the mobility of the machinery.
Who is BS EN 12110 - tunnelling machine airlocks for? 
BS EN 12110 on safety requirements for tunnelling machine airlocks is useful for: 
- Manufacturers and suppliers of tunnelling machines
- Designers of tunnelling machines
- Maintenance crews
- Quality control personnel
- Contractors / builders / architects / engineers
- Safety regulatory bodies
BS EN 12110 is also useful for relevant government / municipal bodies or others who commission the project.
Why should you use BS EN 12110 - tunnelling machine airlocks?  
Tunnels have been shown to be less expensive than bridges or open cuttings for transporting public utilities such as water, sewage, and gas. Airlocks can be connected to tunnelling machinery. BS EN 12110 can help the design of airlocks and bulkheads in other compressed air work in construction.
BS EN 12110 deals with all significant hazards, hazardous situations, and events relevant to such machinery when they are used as intended and under conditions of misuse which are reasonably foreseeable by the manufacturer.
The machinery and equipment concerned and the extent to which hazards, hazardous situations, and events are covered are indicated in the scope of BS EN 12110 which require action to eliminate or reduce the risk.
BS EN 12110 provides guidance on the list of significant hazards, safety requirements and/or protective measures, verification of safety requirements and/or protective measures, signs, signals, and warning devices. General requirements, personnel locks, material locks, combined locks, pressure bulkheads are also discussed in BS EN 12110.
BS EN 12110 is useful to avoid disturbing or interfering with surface life and traffic during construction. The airlock is designed to accommodate an emergency power supply which is power safety-critical equipment in event of a failure of the main power supply.
Verification of compliance with the safety requirements given in BS EN 12110 is made by calculation, inspection, and, whenever feasible, testing during manufacture, or on assembly at site.
BS EN 12110 guidelines enable you to design construction, equipping, marking, and testing of airlocks from project inception through to the end of the service life of the tunnel and ensuring safety, the usability of tunnelling machines.
What’s changed since the last update?
BS EN 12110:2014 supersedes BS EN 12110:2002+A1:2008 which is withdrawn. BS EN 12110:2014 includes some technical and editorial changes with respect to BS EN 12110:2002+A1:2008. These include: 
- General revision of the structure of EN 12110
- Revision of fire protection requirements
- Revision of the access dimensions on airlocks
- New structure of requirements for electrical equipment and the emergency provisions for power supply and lighting
- Revision of requirements for oxygen supply 
