Which of the following statements correctly describes the acceptable porosity in a weld?

• A. Visible porosity less than 10 mm in 25 mm of weld
• B. Visible porosity less than 20 mm in 300 mm length of weld
• C. Any pore shall be less than 2.5 mm
• D. All of the above

Answer: (D)

Porosity acceptance relies on controlling both how big pores can be and how many appear along a weld. The first criterion limits how much porosity can exist in a short segment: in any 25 mm portion of weld, the total length of visible porosity must be under 10 mm, preventing a dense pocket of pores in a small area. The second criterion extends this idea to a longer segment: in any 300 mm length of weld, the total porosity length must stay under 20 mm, ensuring porosity isn’t piling up over longer runs. The third criterion sets a size cap on individual pores: no single pore may exceed 2.5 mm, so large pores that could act as weak points are not allowed. Since a weld must meet all three limits to be acceptable, all of these statements describe acceptable porosity criteria, so all of the above is correct.