The latest revision of NORSOK Standard C-004, Edition 2, published in May 2013, supersedes the previous 2004 edition.
One of the main changes is regarding the helideck drainage and passive fire suppression:
Section 13: Helideck materials and fabrication
…The helideck shall be of a “safe deck” type aluminium construction with a system of extruded profiles. The profile design shall allow for integration of required deck friction, recessed drainage, passive fire suppression, DIFFS, heat tracing, tie-down points and other specified requirements…
Section 17.2 Helideck drainage and passive fire suppression
…The entire helideck area shall be provided with a recessed drainage and passive fire suppressive system in order to ensure optimal rescue and fire fighting conditions…
NOTE: A passive fire suppressive system will not only reduce the extent of fire on the deck, but will also have a damage reducing effect in the event of a delayed DIFFS activation, or even system failure in the worst case.
The drain openings shall be densely and evenly distributed on the deck to ensure quick and effective drainage. This will also prevent pools of spilled fuel on the deck in the event of a helicopter accident scenario.
The drained liquid shall flow directly into the enclosed drain system, which may form part of the helideck profile system. The essential design requirement is that the system’s profiled shape shall have a passive fire suppressive quality that will quickly kill any burning fuel by oxygen starvation (and firewater), while also providing a certain cooling effect