It is the maximum amount of Weight that can be loaded on a unit area. Expressed in t/m2.
it prevents the back flow of the I.G into engine room
Deck seal is provide mainly on Oil tankers to prevent backflow of vapours(HC or Ig) back to the IGG plant.
Deck seal is of three types:
2.Semi wet type
On chemical tankers if deck seal is absent then Block and Bleed valve arrangement will be there