I have a question regarding Clause 6.2.5 of NFPA 415 Standard on Airport Terminal Buildings, Fueling Ramp Drainage, and Loading Walkways which states:
- During a ramp fire emergency, walkway interiors shall have a positive air pressure delivered from a source that shall remain uncontaminated.
Unfortunately the standard does not provide quantitative measures to determine whether positive pressure has been provided. Whilst compliance with NFPA 415 can be readily achieved for the fixed link component of the loading walkway, it is not easily obtained for the aerobridge component. An aerobridge is a telescopic piece of equipment with gaps at the joints and at the point of connection to the fixed link or terminal to allow movement of the aerobridge. These joints allow significant leakage which hinders pressurisation of the aerobridge. Experience has shown that even if pressurisation fans are installed in the fixed link, leakage along the aerobridge means that there is no airflow or pressure differential at the connection between the aircraft and fixed link. The lack of pressure differential and size of gaps between the aerobridge canopy/ skirt and aircraft may then allow smoke to enter the aerobridge at this connection point.
I am based in Sydney, Australia and was wondering how pressurisation for aircraft loading walkways are designed in the US to achieve compliance with NFPA 415.