How many gauge readings does SSPC-PA 2 require within a 4 cm (1.5 inch) diameter circle?

Good records can provide maintenance departments with detailed information about ALL of the following EXCEPT

When using a sling physchrometer a very large difference between the wet and dry bulb readings indicates:

You are the NACE Inspector on a job where the Owner's specification requites you to perform a twice daily check of blast pressure at the nozzle. It is now day 30 on the job and all of your readings have been within compliance. The Contractor complains that these checks taking up much time and in view of the compliant results they are unnecessary.
Your FIRST preferred course of action is to:

Checking is