The process of directly adding foam concentrate to an apparatus booster tank is called which?

• A. Premixing
• B. Direct injection
• C. Foam dilution
• D. Batch mixing

Answer: (D)

When foam concentrate is added directly to the apparatus booster tank, you’re creating a defined amount of foam solution inside that tank before it’s pumped. That approach is batch mixing: you measure a specific amount of concentrate, add water (the booster tank is filled to form a complete foam solution), mix it, and then the pump draws from this single batch as needed. This is different from injecting concentrate into the water stream through a proportioning device (direct injection), or mixing concentrate with water in a separate container or line before introducing it to the system (premixing). It’s also not just diluting the concentrate; you’re preparing a complete, ready-to-use batch of foam solution in the booster tank.