Do the rules of blitz chess allow a draw to be claimed if the position is dead drawn? Consider this objectively drawn position that occurred in the Fischer vs Spassky 1972 match, game 12. Suppose this position occurred in a blitz game where Black barely has few seconds remaining on his clock. Black decides to give up the f5-pawn and instead sit comfortably with his pawns on f6 and h6 as follows-
   [fen &quot;8/5p2/6kp/p4p2/2B5/1P2PK1P/8/4b3 w - - 0 1&quot;]

   1. Kf4 f6. 2. Bd3 Bb4. 3. Bxf5+ Kg7. 

This position is an impenetrable fortress. Because of the presence of bishops of opposite color, there is no way White can check the Black king or even try to win a pawn by attacking it. If White marches up the e-pawn, Black can simply capture. There is no way White can win. Black simply has to keep moving his bishop safely on the a5-e1 diagonal.
Now, since this is a blitz game and Black just has a few seconds left, White simply attempts to run Black out of time just by making legal moves without making any kind of progress. In such a scenario, would Black be allowed to pause the clock and claim a draw?
No. There is a rule like that for standard time controls (rule 10.2 under FIDE rules), however under blitz rules 10.2 doesn't apply. Appendix B, rule B.3.b:

b. Article 10.2 and Appendix A.4.c do not apply.


In blitz, the clock is just as much a part of the game as the board is. If you have a position like that with seconds left and your opponent has more, you are lost.