does this also cover the question:::
2007 edition::
6.3.2* Steel Pipe — Welded or Roll-Grooved. When steel pipe referenced in Table 6.3.1.1 is used and joined by welding as referenced in 6.5.2 or by roll-grooved pipe and fittings as referenced in 6.5.3, the minimum nominal wall thickness for pressures up to 300 psi (20.7 bar) shall be in accordance with Schedule 10 for pipe sizes up to 5 in. (125 mm), 0.134 in. (3.40 mm) for 6 in. (150 mm) pipe, 0.188 in. (4.78 mm) for 8 and 10 in. (200 and 250 mm) pipe, and 0.330 in. (8.38 mm) for 12 in. (300 mm) pipe.
nfpa 13 2013
6.3.2* Steel Pipe — Welded or Roll-Grooved. When steel pipe referenced in Table 6.3.1.1 is used and joined by welding as referenced in 6.5.2 or by roll-grooved pipe and fittings as referenced in 6.5.3, the minimum nominal wall thickness for pressures up to 300 psi (20.7 bar) shall be in accordance with Schedule 10 for pipe sizes up to 5 in. (125 mm), 0.134 in. (3.40 mm) for 6 in. (150 mm) pipe, 0.188 in. (4.78 mm) for 8 in. and 10 in. (200 mm and 250 mm) pipe, and 0.330 in. (8.38 mm) for 12 in. (300 mm) pipe.
2010 edtion::
6.3.2* Steel Pipe — Welded or Roll-Grooved. When steel pipe referenced in Table 6.3.1.1 is used and joined by welding as referenced in 6.5.2 or by roll-grooved pipe and fittings as referenced in 6.5.3, the minimum nominal wall thickness for pressures up to 300 psi (20.7 bar) shall be in accordance with Schedule 10 for pipe sizes up to 5 in. (125 mm), 0.134 in. (3.40 mm) for 6 in. (150 mm) pipe, 0.188 in. (4.78 mm) for 8 in. and 10 in. (200 mm and 250 mm) pipe, and 0.330 in. (8.38 mm) for 12 in. (300 mm) pipe.