HOW TO SELECT THE RIGHT POWDERS ?

Insist on ISO-9002 certified manufacturer.

Ask for  90% base material,  check up at your end or independently by 
reputed & reliable test house for % base.

Ask for Foam compatible powders.

Ensure that manufacturer has license for more than 10 years standing.
Ask for 100% waterproof, hermetically sealed packing.

Look for overall strength of the manufacturer-capacity, R & D and Quality systems.

If your risk is of high magnitude, use only Olfex - PBC - Urea Reaction Product.

If your risk is Metal Fires, use only TEC powder.

    HOW TO SELECT THE RIGHT FOAMS ?

If you want AFFF, ensure that you are not getting Synthetic foam, which can 
be tested by Film Formation Test as follows :-

Take a petri dish ( @ 10 cm diameter ).  Pour 30 ml of  n-heptane / Petrol.  
Make 10 ml, 3% foam solution by
agitating in a beaker.  Pour this foam solution on the fuel surface carefully.  
Move lighted match stick  or lighter flame over the petri dish at about 1 cm 
height if aqueous film is formed, fuel will not catch fire, which will be case 
for good AFFF Foam.  Fuel will catch fire if the foam is Synthetic Foam or 
an inferior AFFF.

Ask for proof of Fluorocarbon Surfactant regular import by the foam manufacturer.  AFFF cannot be made without fluoro carbon surfactant.  There is neither an indigenous manufacturer of fluoro carbon surfactant nor there is any substitute available anywhere in the world.

Check manufacturer background as mentioned under powders.

If high risk is involved or high quality product is required ask for UL listed Foams.

If you are looking for higher Burn-Back & Fastest knockdown, ask for film Forming Fluoro Protein Foam.