According to the NFPA 24 edition 2013 in particular Chapter 10 Underground Piping and document annex detail (Piping brought up through the floor), for the fire network application the following questions is developed:
1) Is allowed to be used steel pipe (ASTM A 106 Gr B) in underground fire protection service?
2) Is allowed the use of Flange in steel (ASTM A 105) underground fire protection service?
3) Is allowed the use of Flanges in underground services (as shown in Fig. 1 attached), means Flange in PRFV joint with Flange in Carbon Steel as a transition point? The flanges are going to be wrapped?.
4) What type of the material in screws and nuts is allowed to use underground Joining of Pipe (flanges)?