Fire pump controllers - new European norm
Published: 01 June, 2007
In September 2007 a European Norm standard EN12845 will come into force. This is a fire sprinkler specification which includes a definition for the fire pump controller.
In the UK, the LPC has already started to adopt the standard and it will be mandatory by September. The diesel engine controller to the EN12845 is very similar to the LPC rules, but with an alternative crank sequence, a low fuel level monitor, a jacket heater output and a low jacket water temperature alarm.
Most other countries have to yet to fully embrace the new standard. Only time will tell how successful this standard is in terms of harmonising the fire sprinkler code through out Europe.
Rules & regulations
There are many different fire pump installation rules and regulations throughout the world. The nearest thing we have to a world standard is the NFPA 20 (National Fire Protection Association pamphlet 20). NFPA 20 originates from the USA. FM uses the NFPA20 specification as their guidelines when approving controllers.
To complicate matters further, some people prefer to use NFPA 20 as the basis of the fire pump, but do not have it approved by FM. In this mode, the fire pump set is referred to as UNLISTED and is a lower cost option to the FM approach.
No matter which fire sprinkler standard is used in Europe, the fire pump controller must be CE-marked, which covers the machinery and safety directive, the low voltage directive and the electromagnetic compatibility (EMC) directive.
Very generally this means the controller must be tested for fast transient voltage burst, radiated emissions, radiated immunity, conducted emissions, conducted immunity and electrostatic discharge.
Future Trends
Due to diesel engine developments, and also as a result of rapid developments in information technology, the whole field of fire pump control is likely to change dramatically over the next few years.
Already we are seeing the change to electronically controlled diesel engines. This has come about due to the various world standards limiting emissions from diesel engines, but brings with it benefits in terms of higher levels of information from the engine systems.
When integrated with the advances in the controller systems, this will enable a greater capability for remote monitoring and management of the fire pump system.
Engine and controller manufacturers will be able to undertake remote fault analysis from their factories, and guide onsite maintenance staff to a correct repair solution should a fault occur, without the need to send specialised service engineers to far-flung corners of the world
Diesel engine driven pumps
The standard NFPA20 specifies in detail the correct operation of the fire pump system and in particular the controller functions. On a diesel set, there are two engine starter batteries fitted, either a 12v or 24v set.
NFPA 20 additionally specifies that the engine shall be started once a week automatically via a weekly start timer in a test mode. The diesel fuel tank level must also be monitored and when the fuel level is low, a low fuel level alarm on the controller is activated.
Electric motor driven pumps.
The main components in a NFPA20 electric motor controller are an Isolator switch sized >115% FLC (full load current) of motor, contactors, either Direct on Line or Star Delta (horse power rated), a circuit breaker sized to >115% FLC of the motor, logic circuit with various monitoring channels and an emergency start mechanism for starting when the control circuit has failed.
To correctly specify an electric motor fire pump controller you must of course know the motor kW or HP rating along with the supply voltage. The starting method must then be chosen. The following methods have been traditionally used in Europe:
* Direct on line or across the line, up to 100kW (MP300 type)
* Star delta or wye delta reduced starting method for over 100kW. (MP430 type).
NFPA20 now specifically allows this method of starting although the controller must also have an emergency direct on line by pass contactor included.
The above mentioned diesel engine or electric motor controller will automatically start the pump once it detects a drop in water pressure. Usually a jockey pump is included on an installation in order to maintain a steady water in the system.
When FM is not the insurer, then the building can be protected by a fire sprinkler that is manufactured to local rules.
Most countries throughout Europe have their own set of standards.
