Our expert responds #10

QUESTION
What are, according to UNI EN 12845, the power characteristics that a diesel motor must possess in order to be suitable for controlling a main fire pump?

ANSWER UNI EN 12845 in point 10.1

In the next image, the points of the characteristic power curve are indicated, which must be considered for the calculation of the motor power (whether diesel or electric).

In particular, diesel motors having to comply with point 10.9.1 have to deliver the required power according to the curve NA: Overloadable continuous power 10% DIN 6271 - ISO 3046-1

The diesel motor must therefore have a greater power than that required by the pump in question, in particular:

• For pumps with a characteristic power curve without overload, higher than the maximum power absorbed at the peak of the power curve – to be precise the VTPs
   
• For pumps with a characteristic curve of increasing power, greater than the power absorbed by the pump when to operate it requires an NPSHr of 16 m – to be precise, the single-rotating centrifugal machines

and shall be capable of providing such power, continuously at full load, at the installation quota in accordance with ISO 3046. In the slide this curve is identified with the NA curve.