World Wide Metric

Understanding Storm Valves

What Is A Storm Valve?

Storm valves can be found in everyday marine systems. Normally, they are situated in sanitary piping systems that have a ship-side exit. These valves can prevent waste from back flowing into the system during rough sea conditions. These valves, also called ‘scupper valves’ or ‘discharge check’ valves, can be found and used on overboard discharge lines to remove sanitary wastes or wastewater.

A storm valve is essentially a swing-check valve with a closing device. The closing device helps control flow with either a manual wheel or actuated system. The valve functions offer either fluid isolation or non-return.

How Does A Storm Valve Work?

Gray Vertical Type Storm Valve

When working with a storm valve, you will notice that there are two openings – the inlet and the outlet. Quite simply, fluid flows in through the inlet and out through the outlet. Inside the valve is a flap attached to a counterweight and locking block. The locking block is the piece of the valve controlled and operated by the external hand wheel or actuator. The purpose of the locking block is to hold the flap in place, preventing fluid flow.

Once flow begins, the operator must choose whether to open the locking block or keep it closed. If the locking block is closed, the fluid will stay out of the valve. If the locking block is opened by the operator, fluid can flow freely through the flap. The pressure of the fluid will release the flap, allowing it to travel through the outlet in one direction.

Gray Angle Storm Valve

The flap will automatically return to its closed position when the flow stops.Regardless of whether or not the locking block is in place, if flow comes through the outlet, the backflow will not be able to enter the valve due to the counterweight. This feature is identical to that of a check valve, where backflow is prevented so that it will not contaminate the system. When the handle is lowered, the locking block will secure the flap in its closed position again. The secured flap isolates the pipe for maintenance if necessary.

Storm Valve Tests

The hydrostatic test is the most beneficial test for your storm valve. A hydrostatic test will test your storm valve for strength and leaks. To perform a hydrostatic pressure test on your storm valve, view the video below and follow the steps below:

  1. Open the valve to a fully open position.
  2. Attach gauged disk to flange (outlet)
  3. Fill the valve cavity with water
  4. Block off the flange with a blank disk (inlet)
  5. Raise pressure to 723 KPA for 3 minutes
  6. Check the body for leaks
  7. Release pressure
  8. Lower handle to fully closed position
  9. Remove the blank disk
  10. Vacate the valve cavity of water. Now only the inside of the valve (where backflow would potentially be) is only filled with water.
  11. Raise pressure to 482 KPA for 1 minute
  12. Check the seat for leaks
  13. Release Pressure
  14. Raise the handle
  15. Raise pressure to 482 KPA for 1 minute
  16. Check the seat for leaks
  17. Release Pressure
  18. Remove gauged disk from the flange.
  19. Lower handle

The standard body and seat test is performed on this valve. However, the seat test is conducted as two separate tests with the handle raised and lowered. It is important to note that due to the purpose of this valve, the pressures are not rated as high as other valves.

World Wide Metric is one of the leading suppliers of valves and fittings, aligning with the requirements and standards of the Maritime and Industrial Flow Control and Fluid Power markets. Get in touch with us to get your storm valves and other equipment for your marine and industrial needs.

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