It is a common failure in many pump sets, or so we thought, when Factory Acceptance Tests (FAT) are induced, that the pump underperforms its original rating. We often think that this is caused by insufficient drivers, or a defect in the pump coupling is present. Well, why don't we take a deeper look into it?

Centrifugal Pump Performance Drop: An Overview

To evaluate a pump's performance fairly with notice of every factor, every factor must be taken. This includes environmental factors, which sometimes are ignored by certain parties. This causes the engine to not perform as expected. 

Engines experience a 3% performance drop from its standard SAE conditions for every increase in 1000 ft of altitude above 300 ft / 91.4 m increase of its rated capacity. This has a direct impact on the pump set's performance. Take for example, a 200Hp engine. The engine, being installed on altitude 1828 ft above its rated environment experiences a total of 6% performance drop. This means that the raw power being transmitted to the shaft is about 188Hp. In accordance to this, the pump set has 12Hp less power than before, resulting in pump underperforming. 

Other factor such as air temperature, in which a deduction of 1% power can be taken for every 5.6 deg. C increase above 25 deg. C ambient temperature. Other causes for performance drop includes the air's humidity, oxygen content, air filter cleanliness and other unknown factors can directly or indirectly impact pump performance. engines stored in a damp, dust filled warehouse without regard to the guidelines requires to be treated and maintained properly to expect the most performance.

To compensate for the perfomance drop, the following options can be considered:
1. Take into complete consideration, all environmental & external factors that may affect engine performance.
2. Add a multiplying factor of pump net power to avoid the loss.
3. Increasing the engine's fuel rate by 3% per 1000ft (305m) increase of altitude.
4. Increasing the fuel rate by 1% per 10 deg. F or 5.6 deg. C above 25 deg. C ambient temperature