1. Introduction

FIREMIKS is a water motor driven foam dosing system using two types of pumps to dose the concentrate into the water. Piston/plunger pumps (PP) and Gear pumps (GP). The basis for the correct dosing to work is that the pumps can pump the expected amount of concentrate for a given water flow. The approved dosing range (NFPA, FM, UL, EN, etc) for a 3% foam is 3,0 to 3,9%. One important factor is the viscosity properties of the concentrate and the using temperature. This report will look closer into the performance of a new Dr. Sthamer F3-AR* concentrate and our recommendations on how it is best dosed using FIREMIKS equipment.

1.1. Impact of viscosity on the performance of different pump types

FIREMIKS uses two pump types because they complement each other when it concerns the viscosity of different types of concentrates.

1.1.1. Piston/plunger Pumps (PP) is a reciprocating pump and perform at their best at low and medium viscosities.

1.1.2. Gear Pumps (GP) on the other hand perform best with high viscosity as their action is continuous and the gears will easily ‘grab’ the high viscosity fluids.