Hydraulic Study Calculation for Sprinkler System in BPCL LPG Bottling Plant, Thanjavur

Bharat Petroleum Corporation Limited (BPCL) LPG Bottling plant Thanjavur has entrusted M/s iFluids Engineering to study the existing fire water arrangements and its adequacy inside the bottling plant sheds. The existing firewater network is categorized into 14 different fire zones with deluge valve actuations. Sprinkler arrangements and Fusible loop connections for fire detection are available in the plant. M/s iFluids Engineering conducted the detailed site survey for the existing fire water arrangements, As-Built drawings, Pressure monitoring and other required data collection to check the adequacy of existing Fire water arrangements.

Bharat Petroleum Corporation Limited (BPCL) LPG Bottling plant – Thanjavur consists of the following facilities.

  • Filled shed- 2 Nos. (DV-1 & 2)
  • PT shed – 1 No. (DV-3)
  • Filling shed- 5 Nos. (DV-4, 5, 6, 7 & 8)
  • Gantry – 2 Nos. (DV-9A & 9B)
  • Bullet Area – 3 Nos. (DV-10, 11 & 12)
  • LPG Pump House – 1 No. (DV-13)

The Scope of Work for M/s iFluids Engineering

  • To Determine Water demand and No. of sprinkler nozzle calculation for 14 nos. deluge system
  • To perform Hydraulic calculation of above mentioned 14 nos. deluge valves
  • Network hydraulic calculation considering water flow from deluge valves in consideration with nearby hydrants and Monitors (Each DV should take 3 monitors and one Double Hydrant into consideration)
  • To provide the detailed Spray nozzle arrangements to achieve the spray density in LPM/SQM

Execution Methodology

Data Collection

  • PFD & P&IDs of the Firewater arrangement including Fire Water tanks.
  • Fire water system overall layout for the Process units.
  • Isometric and Piping GAs for firewater network showing sprinkler system for each facility.
  • Equipment datasheet for Water monitors, hydrants, deluge valves, HVLR’s and orifice plate.
  • Fire Water sprinkler system for storage tanks details including the K factor of sprinkler nozzles   Number of water sprinkler rings in each area.
  • Firewater pump datasheet including Main and Jockey pump.
  • Fire Water Piping specifications.
  • Operating philosophy of fire water system.
  • Fire and gas philosophy and its cause and effect, showing fire zones with respect to their deluge valves opening.
  • Existing Hydraulic analysis Report (if available)
  • PFD & P&IDs of the Foam System for facilities fire water arrangement including Fire Water tanks.
  • Isometric diagrams and Piping GAs for Foam network.
  • Foam system operating philosophy and pump datasheet.

 Hydraulic Study Procedure

  • Standard software for hydraulic analysis of firewater systems in compliance with NFPA13, NFPA15 and NFPA16 rules was utilized for the modelling.
  • This module for hydraulic analysis adheres to national and international standards. It is Ideal for the design of systems used in critical applications such as offshore platforms, petrochemical plants, power plants, terminals and refineries.
  • Fire water equipment such as Water monitors, hydrants, deluge valves, HVLR’s and orifice plate data was fed.
  • Fire water pump including main & jockey pump characteristic curve was incorporated for pressure and flow rate from the pump house.
  • Fire water pipeline data was taken from piping class specification.
  • Firewater flow line size and line length was incorporated from overall layout file or site survey report.
  • Firewater model was primarily drawn from pump house and flow lines were extended to respected main headers & sub headers.
  • Initially Firewater pumps were drawn from characteristic curve & optimized for BEP. Checked for output pressure, flow rate & Efficiency.
  • Overall layout of the firewater network was drawn adding Water monitors, hydrants, deluge valves, HVLR’s and orifice plate in the main header and sub header flow lines.
  • Fire water flow lines were extended to each Process facilities and storage tanks. Similarly, Water monitors, hydrants, deluge valve, HVLR & orifice plate was added.
  • Similar to fire water network, foam system was added to storage tanks along with the nozzles.
  • While adding nozzles such as water monitor, hydrant, deluge valve, HVLR, should be checked for off position.

Software Modelling

  • The pipe network modelling was carried out in a standard Software.
  • After modelling, the flow lines for all the facilities along with the nozzle and sprinkler system were included. The model was corrected for any errors if occurred.
  • The modelling was run for two simultaneous fire and HVLR, Monitor, hydrants to be opened as per NFPA. All other sections of the facility nozzles were in off conditions or the scenarios were considered as per Client provided details for worst case scenario.
  • Fire water pumps were checked for flow, pressure and the number of pumps to be line depends upon the fire water demand, pump capacity and the fire water flow line network.
  • Iterations were done in flow line size i.e., main header or sub headers based on the required pressure and flow rate in a section.
  • Flow lines should also satisfy the velocity limit given in NFPA. Iteration to be done flow line size if the velocity exceeds. Optimization to be done such that given pressure and velocity is achieved for a given flow rate.
  • Followed by iteration in Flow lines, iterations were done in Fire water main pumps and jockey pump was added even if required flow rate and pressure was not achieved.
  • Fire water demand calculations were performed for each storage tanks, bullets, storage spheres & Process units as per NFPA.
  • Minimum fire water storage should satisfy the fire water demand for firefighting as per NFPA.
  • Foam requirement in specified storage tanks had to be satisfied.

Outcome of the Study

  • Pipe sizing for new and retro fire water pipe networks.
  • Calculation of pressure drop in fire water pipes for existing piping networks.
  • Calculation of velocity in fire water flow pipes.
  • Selection of fire water main pump, jockey pump & restriction orifices.
  • Ensuring that all consumers will be supplied the demand amount of fire water for distribution networks.
  • Ensuring that all nozzles get desired water flow rate and pressure for fire-protection network.
  • Fire water demand for fire protection.
  • Hydraulic analysis.