Air Valve - Vapor Volume Calculation

Dear All,

I have modeled my case using real air valve data. At one place it's showing large vapor volume. Surge is under the permissible limit.

Can a air valve handle this volume or what should I do to reduce the vapor volume ?

Air valve spec details also attached.

Model has add one 50mm dia double acting air valve at the pump house and 100mm dia. Triple acting air valves at about 250-300m, 800-850m, 1150m distances.

Looking forward to hearing from you.

Thank You.

Ishanka Wimalaweera