Offshore Facilities pre start-up Audit Questionnaire

Onshore drains construction

The main concern is the prevention of large inventories of flammable liquid or gas and its ignition. This is achieved through correct drain line gradients, the siting of sumps and the removal of ignition sources from open points.

Do the sump drainage areas comply with the following layout and location criteria:

  Do drainage sumps in paved surfaces serve an area of approx. 400 m2?

  Is the maximum distance between sumps around 20 m?

  not more than 50 m unless diameter > 900 mm?

  Is the distance between an open sump and any open flame burner at least 7.5 m?

  Is the high point of a 20 x 20 m sub-catchment area at least 100 mm?

  Are adjacent roads at least 200 mm higher than high-point of paving?

Do the sumps themselves comply with the following:

  Is the bottom of the sump a minimum of 200 mm below lowest connected pipe;

  Are pipe ends flush with inside sump wall for self-skimming buckets;

  Are sumps provided with suitable galvanised grating covers;

  Are closed sumps fitted with 50 mm vents where hydrocarbon vapours can accumulate;

  Are self-skimming buckets provided in AOC systems.

Does drainage piping comply with the following:?

  Are all underground drainage pipes in excess of 200 mm diameter?

  Are all drainage pipes laid horizontally?

  are they kept flooded?

  Is the drainage system flushed every six months?

  Is the underground piping GRE, steel or concrete?

  Do all pipe tracks have a free run-off (1:200 mm) towards drain channel?

  Is the pipe track at least 250 mm below the sleepers to allow inspection?

Do open drains channels comply with the following:

  Are channels at the foot of embankment provided with 350 mm walking strip?

  Do large open drain channels (>900 mm wide) have central flow channels?

Do fire traps/breakers comply with the following:

  Are fire traps and sand traps installed at road crossing?

  are there fire breakers within pipe tracks?

  Do the fire trap sumps meet minimum requirements as drainage sumps?

  Is the distance between two connected fire trap sumps > 9.0 m

  is the connecting underground pipe always liquid filled?

  Are sand traps provided upstream of every fire trap?

  are they the same width as the drain channel?

  do they have a minimum length of 1.0 m and depth of 0.5 m?

Is concrete blinding provided for pipe tracks handling light products.