B737 Loss of Thrust both engines. Rate of cabin depressurisation
 

Assuming loss of thrust on both engines (B737) at 35,000 ft. During the subsequent glide while attempting relight, what average depressurisation rate (cabin rate of climb in feet per minute) could normally be expected?
The QRH recommends specific airspeeds to facilitate relight. Is there any correlation between IAS used and rate of climb of cabin?

Rate of cabin climb depends entirely on how well sealed the entire 'pressure vessel' of the airframe is. I don't think IAS will come into the equation at all.

It was once demonstrated to me on a virtually new airframe at the time (a 747 classic). The training Flight Engineer turned off each of the three packs at FL350When the last pack was turned off the cabin climbed at about 100 ft/min.

However once on an old 737-300 we had a duct split at FL330 and the cabin climbed at about 1000 ft/min necessitating an emergency decent.

I've been lucky to try, during some maintenance test flights after the checks, the "Cabin Leak" test on B737 Classic.

After switching off both Packs, the cabin altitude climbed at an average of 2500 ft/min. They were not brand new airplanes of course :}