The purpose of this procedure is to define the step by step method to implement the correct practices for the pre commissioning & commissioning of “Fuel Oil System” through the guidelines contained herein so as to ensure that the job execution complies with the project requirements and serves the intended function to satisfactory level.
Pre Commissioning Procedure for Fuel Oil system
- Ensure that the system installation is complete and mechanical completion is approved.
- Ensure that no damage has occured between mechanical completion & precommissioning.
- Repair all damages to the equipment & piping.
- Check that the Fuel Oil piping network is complete with proper filling pipe valves & pressure switches in place as per final approved shop drawing.
- Ensure that the Fuel Oil network is pneumatically pressure tested and approved as per method statement & specifications.
- Ensure that the entire system is cleaned internally & externally.
- Ensure that the fuel oil pumps are as per approved material submittal.
- Ensure that the fuel oil pumps are precommissioned and commissioned in line with the approved procedure.
- Ensure all the weather proof pressure switches, motorised valves, line filter, isolating valves, NRV,PRV, pressure gauges are installed & wired properly.
- Ensure the wiring to the DDC & fire alarm panel from the pump panel is complete & power supply to panel is complete.
- Ensure that BMS connections are done.
Commissioning Procedure for Fuel Oil System
- Ensure that all the precommissioning checks are carried out successfully.
- The Fuel Oil system shall be completed & tested for proper sequence of operation as defined below.
- The Fuel Oil System consists of 2 fuel oil pumps, 2 day tanks, 2 solenoid valves, 2 mororised valves, 2 level sensors, one pressure switch & 4 fire valves.
- In case of failure of the duplex pump sets or electric motors, same capacity hand operated pump is to be used. This pump shall be provided during project hand over.
Sequence of operation For Fuel Pump
- Pump Start Sequence: When the Fuel oil level in any of the two day tanks fall below the specified level, the low level switch in the day tank shall trigger the pump start sequence, which is as follows:
a. The solenoid valve in the corresponding day tank shall open.
b. The motorized valve at the suction of the pump (duty) shall open.
c. The pump shall start.
- Pump stop sequence
When the Fuel oil level in any of the day tank goes above the specified
level, the high level switch shall trigger the pump stop sequence,
which is as follows :
a. The pump stops
b. The motorized valve at the suction of the pump (duty) shall close.
c. The solenoid valve of the corresponding day tank shall close.
Dry run protection: When the pump starts and the pressure at the discharge of the pump sensed by the pressure switch is < 0.4 bar for a period of 2 minutes the pump shall stop to avoid dry run. This is explained in the demonstration procedure below.
Stand by operation: When the duty pump fails to start even after receiving a start command,
the standby pump shall start . Fault shall be shown on the panel.
Swapping of pumps to achieve equal operating hours: The duty and standby pumps shall be swapped after a specified period of operation to have uniform wear and tear of pumps using cyclic timer.
Valves that are normally closed & normally open:
1. Solenoid valves in day tank – Normally closed.
2. Motorised valves at the suction of the pump – Normally closed.
3. Fire valves – Normally open.
Manual operation: Auto / Manual selector switch shall be provided. Manual start / Stop buttons and lights to be provided in the panel for duty and standby pump. During manual operation of pumps, all the relevant motorized valves & the solenoid valve in day tank shall open.
Interlock with fire alarm & BMS: A volt free N/O contact from Fire Alarm system shall be provided to
the panel. This shall be multiplied and interlocked with the power supply to fire valves so that the valves are normally open but close in the event of contact becoming N/C. The pumps shall start running only
when this contact in normally open.
Pump start / stop sequence
- The diesel level in the day tank shall be lowered by draining the diesel using the drain valve in the tank.
- This will activate the level switch, which will convey a signal to the pump panel for stating of the pump.
- The solenoid valve in the day tank & the motorized valve in the pump suction shall open & then the pump will start.
- Once the pump starts & the diesel level in the tank rises, the high level switch will activate & the pump shall be stopped. Subsequently the motorized valve & the solenoid valve will close.
- Dry run protection: The pump shall be started & the valve in the suction line of the pump shall be closed which will cause the pump to starve for fuel. When there is no fuel to pump, the pressure in the discharge line shall reduce. When the discharge pressure is < 0.4 bar for a period of 2 minutes, the control panel will initiate a shut down of the pump. The set point of 0.4 bar is selected because the pressure switch range is from 0.4 to 2.5 bars.
Stand by operation: The pump set shall be started in auto mode & made operational. After allowing duty pump to run for few minutes it shall be switched off manually & the automatic starting of the other pump shall be observed.
Swapping of the pumps to achieve equal operating hours:
- The duty & standby pumps shall be swapped during every cycle to achieve equal operating hours. This shall be verified as below:
- The pump set shall be started in auto mode, the duty pump will start & it shall be made to run for few minutes.
- The pump set shall be switched off & again started. This time the standby pump will start & act as duty pump.
BMS interface: The following parameters shall be monitored by BMS:
– Pump run/fault status
– Fuel tank level status