Problem:

What Class of Member does the allowable tensile stress refer in paragraphs (1) and (2)?

Solution:

Refer to BD 24 and BD 37.
BD 24 Clause 2.7 says that all prestressed concrete members shall be checked as being in Class 2 in load combinations 2 to 5.
BD 37 Clause 5.9.1.2 says that temporary erection loads are considered in Combinations 2 and 3.
Thus for a prestressed beam during construction, at transfer the beam is considered as a Class 2 member and tension is allowed under the loading for either condition (1) or (2) in BS 5400 Pt 4 Clause 6.3.2.4(b).
The beam has to be checked as a Class 1 member under Combination 1 loading and as a Class 2 member under Combination 2 to 5 loading.