SECTION 2.3 DETAILED PROCEDURES (NEW)

2.3.1   Bromine Leaks from Fittings

 

Introduction: Typical Valve Arrangement

ISO containers are typically fitted with either two or three valves.  Where three valves are used, the centre valve (the valve centred on the manlid) is used for discharge, one off-centre valve is used for pressuring the container and one off-centre valve is used for venting the container.  When fitted with two valves, the centre valve is used for discharge and the second, off-centre valve is used to both pressurize and vent the container.  Colour coding for the valves can vary by geographic region.  For instance, the valve colours in Europe often differ from the valve colours used in North America.  In Europe, the valve colours typically used are yellow for discharge, green for pressurization and red for the connection of a vent line.

 A diagram of a typical valve arrangement appears below:

2.3.1   Bromine Leaks from Fittings

Notes:

  • for simplification purposes, pressure relief devices are not shown in the above diagram.  See section XX for advice on pressure relief devices.
  • All valves turn clockwise to close and turn counter-clockwise to open
  • Do not over-tighten diaphragm valves.  Over-tightening a valve could perforate the diaphragm.
  • Bromine leaks are often not often obvious.  Aqueous ammonia can be used to help identify the leaks and their location.  When vapours from aqueous ammonia contact bromine vapours a white cloud of ammonium bromide will form.  DO NOT allow liquid ammonia to come in contact with bromine.

 

 

1. LEAKING FROM ABOVE A VALVE

1. LEAKING FROM ABOVE A VALVE

Make sure the leaking valve is properly closed by turning the hand wheel clockwise.

  1. Check the condition of the gasket under the valve blind flange.  Replace if torn, scratched or otherwise damaged.
  2. Reassemble and tighten the valve’s blind flange bolts.

 

2. LEAKING VALVE BONNET OR BODY GASKET

2. LEAKING VALVE BONNET OR BODY GASKET

  1. Remove the blind flange from the vent valve (the valve used for pressure relief).  Relieve any pressure in the vessel by opening the vent valve, slowly and cautiously.  Close the vent valve.
  2. Open the leaking valve by turning the hand wheel counter-clockwise then tighten the four nuts connecting the bonnet to the valve body.
  3. Close the leaking valve and the vent valve.  Check for leaks.
  4. If the leak has not stopped, repeat step a.  Then replace the faulty valve with the gasket and blind flange that had been above the faulty valve.  Ensure a tight connection.

 

3. LEAKING FROM BELOW A VALVE

3. LEAKING FROM BELOW A VALVE

Tighten the nuts on the studs used to connect the valve to the vessel flange.

  1. If the leak continues, dismantle the blind flange from the vent valve (for pressure relief).  Relieve any pressure in the vessel by opening the vent valve, slowly and cautiously.
  2. Remove the leaking valve and check the flanges.  They should be smooth and without deep scratches.  If necessary, carefully smooth out any scratches.
    Check the gaskets and replace if torn or damaged.
  3. Reinstall and then close the valve and then close the vent valve.  Check for leaks.  If there are no leaks, replace the blind flange on the valve.  Ensure a tight connection.
  4. If the leak has not stopped, repeat step b.  Then remove the valve again but replace it upside down.  Check for leakage.
    If there is no leakage, replace the blind flange over the valve.
    Ensure a tight connection
  5. If the leak has not stopped, repeat step b.  Then replace the faulty valve with the gasket and blind flange that had been above the faulty valve.  Ensure a tight connection.

 

4. LEAKING DIP PIPE

4. LEAKING DIP PIPE

Tighten the nuts on the studs that connect the dip pipe flange and valve.

  1. If a leak continues, remove the blind flange from the vent valve (for pressure relief).  Relieve any pressure in the vessel by opening the vent valve slowly and cautiously.
  2. Caution:   
    - Wear full body personal protective clothes and equipment including respiratory and face protection and rubber boots.
    - Remove valve and dip pipe
    - Remember that the dip pipe may be wet with liquid bromine.
  3. Check the flange faces.  They should be smooth and without deep scratches.  If necessary, smooth out any scratches.
    Check the gaskets and replace if torn or damaged.
  4. Reinstall the dip pipe and valve, close the vent valve.  Check for leakage.  If there is no leakage, replace the blind flange over the valve.  Ensure a tight connection.
  5. If the first attempt to reseat the dip pipe and valve does not work and the leak has not stopped, repeat steps 3-5.   Again, remember that the dip pipe may be wet with liquid bromine.
  6. If the dip pipe continues to leak then install a gasket and a blind flange directly onto the container outlet.  Ensure a tight connection.

 

5. LEAKING BETWEEN DIP PIPE FLANGE AND VALVE.

5. LEAKING BETWEEN DIP PIPE FLANGE AND VALVE.

Tighten the nuts of the studs concerning the dip pipe flange and valve.

  1. If a leak continues, remove the blind flange from the vent valve.
    Relieve any pressure in the vessel by opening the vent valve slowly and cautiously.
  2. Remove the valve and check the flanges.  They should be smooth and without deep scratches.  If necessary, carefully smooth out any scratches.
    Check the gaskets and replace if torn or damaged.
  3. Reinstall the valve, close it, then close the red vent valve.  Check for leakage.  If there is no leakage, replace the blind flange over the valve.  Ensure tight connection.
  4. If the leak has not stopped, repeat step b.  Then remove the faulty valve and install the gasket and blind flange in place of the faulty valve.  Ensure tight connection.

 

 6. LEAKING FROM UNDER THE MANHOLE COVER FLANGE

 6. LEAKING FROM UNDER THE MANHOLE COVER FLANGE

Tighten the nuts of the manhole cover.  If possible, use a spanner with a long arm to maximize tightening capability.

 

Leaks from Pressure Relief Devices

ISO containers are fitted with pressure relief devices to prevent over-pressurisation of the vessel, for instance, when exposed to heat from a fire.  ISO containers can be fitted with two types of pressure relief devices.  The more common device is a pressure relief valve (PRV) which actuates to release when container pressure set points are exceeded.  The second type is a fusible element.  The fusible element is typically not used on its own but rather in conjunction with a PRV.  Fusible elements contain a low melting alloy that will melt in a fire situation to increase the container vapour venting capacity.

The drawing below shows an example of the possible placement of pressure relief devices.  Note that placement may vary by container design.  In many cases, a fusible element will not be fitted.

Leaks from Pressure Relief Devices

1. LEAKING FROM UNDER SAFETY VALVE

1. LEAKING FROM UNDER SAFETY VALVE

  1. Tighten the nuts on the studs that connect the vessel flange and the pressure relief device.
  2. If a leak continues, remove the blind flange from the vent valve (for pressure relief).
  3. Relieve any pressure in the vessel by opening the vent valve slowly and cautiously.
  4. Remove the valve and check the flanges.  They should be smooth and without deep scratches.  If necessary, carefully smooth out any scratches.
  5. Check the gaskets and replace if torn or damaged.
  6. Reinstall the valve and then close the vent valve. Ensure a tight connection and check for leakage.
  7. If the leak has not stopped, repeat steps 3-6. 
  8. If the safety valve is still leaking after several attempts at reseating as described above then a piece of lead sheeting can be used as a temporary means of stopping the leak until the container can be fitted with a replacement safety valve.


2. VAPOURS LEAKING FROM UNDER THE FUSIBLE ELEMENT (WHEN INSTALLED).

2. VAPOURS LEAKING FROM UNDER THE FUSIBLE ELEMENT (WHEN INSTALLED).

Tighten the bolts connecting the fusible element to the tank outlet.

  1. If a leak continues, remove the blind flange from the red vent valve (for pressure relief).
    Relieve any pressure in the vessel by opening the red vent valve, slowly and cautiously.
  2. Remove the leaking fusible element.
    Install in place of the fusible element, the blind flange from above the red vent valve.

 

2.3.2   Bromine Spill Response Techniques

A bromine spill or leak is very quickly indicated by reddish-brown vapours and harsh irritating odours.

After the vehicle driver becomes aware of a bromine leak, he should attempt, if possible, to move the vehicle to a less populated area, stop the vehicle, escape the irritating fumes while putting on the escape mask and walk quickly towards a spot higher than the roads, above the bromine fumes. From this safe spot, the driver should stop the oncoming traffic, alert the police, the nearest fire department and the nearest bromine user, if possible. People not properly equipped must be kept out of the area, and depending on the size of the leak, evacuated from the spill danger zone.

Only properly protected and trained responders should attempt to stop a bromine leak, using emergency repair materials (i.e. wooden cones, leadwool, etc) or by freezing the bromine as its escape an opening.

If the bromine is leaking out from between fittings or flanges, the responders should follow the troubleshooting recommendations in 2.3.1. To contain a bromine spill on the ground, earth and sandbag dams should be built around the spill and the contained bromine neutralised.

2.3.3   Sealing  a major leak from a container

Properly trained emergency response personnel have typically been trained to deal with liquid leaks.  Common techniques used for liquid leaks of other chemicals can be utilized for sealing leaking bromine containers.  Note that every leak scenario is different.  A leak sealing technique that is useful under one set of circumstances may not be useful under another set of circumstances.  First responders and chemical emergency responders must responsibly assess a given spill or leak situation prior to taking any actions.

Vapour leaks are generally less pose less severe consequences than liquid leaks.  Consequently, if it is judged safe to do so, a container leaking liquid bromine should be reoriented so that the leak point is confined to the vapour space (i.e. – the hole is above the liquid level in the container).   For instance, if a container has a hole in the very bottom of the container, it should be turned 180° so that the hole is instead at the very top of the container, in the vapour space.  This will minimize the amount of bromine released and make access and repairs to the leak area easier.  Prior to reorienting the container, the integrity of the valves and fittings should be evaluated and confirmed as closed and sound to ensure that the action will just result in a different liquid leak.  This technique will require special lifting.

 2.3.3   Sealing  a major leak from a container

There are different techniques that can be used based on the type of leak and the resources available.   Attempts to seal a container leak, whether vapour or liquid, should only be performed by trained responders outfitted with appropriate PPE.

For leaks from fittings, please see section 2.3.1.  Leaks from the body of the container can be sealed in a few ways.

  • A wooden cone can be used to stop the leak.  In this common leak sealing technique, a wooden cone is hammered into the leak opening to plug the container.  This can only be done in situation where the size of the leak opening makes this possible.
  • Use a leak sealing cushion or pillow to cover the leak. Special cushions for this purpose are available by most of the fire departments. The cushions strap around the outside of the container.  The cushion is either inflated to apply pressure across the leak opening or clamps are tightened to apply pressure.  Other variations of this device include those which adhere to the container using heavy magnets or suction cups.
  • Chemically resistant leak sealing putties have been found to be effective in some situations. 
  • If equipment or expertise is available and the leak has been isolated to vapour only, a steel patch can be welded over the leak opening.
  • Another possibility for consideration, though never practiced, is chill the leak area in order to freeze the bromine to stop the leak. Because bromine freezes at -7 °C this should be considered as a possibility if other means of sealing the leak are not available.

The above leak sealing techniques offer only a temporary solution to immediately contain the bromine.  After the leak is sealed, the remaining bromine should be transferred to another tank as soon as possible.

2.3.4   Tank to tank transfer techniques

After sealing a major leak from an ISO container, the tank should be emptied on the spot if possible.  However, with proper authorization, the container might be carefully moved to a preferred transfer location.  For instance, a location may be more preferred because it is more isolated, is better equipped or will minimize disruption to transportation or the community.

A pressure transfer is the simplest means of transferring bromine from one container to another.  The pressure transfer method can only be used if the temporary repair can withstand the pressure needed to empty the container. If a pressure transfer is not possible then a transfer pump may be used to empty the patched container.  The pump used must be resistant to the corrosive effects of bromine (for example, Teflon, PVDF, viton or ceramic wetted parts)  Regardless of the transfer techniques used a scrubber system is required.

RECOMMENDED PROCEDURE (Two Valve System)
(See figure below for typical set-up and iso-container valve arrangement.)

  1. Wear recommended personal protective equipment.
  2. Assemble an absorber scrubber unit. This can simply be a vessel with caustic soda and sodium bisulphite (if available).  Even better is the scrubber system can be a circulated solution of caustic and sodium bisulphite (if available).  Be sure the absorber unit is working and capable of handling vented bromine fumes.
  3. Use dry air air or dry nitrogen (-40 °C dew point) to transfer the damaged container.  Keep the pressure as low as possible.  During the course of this procedure only apply just enough pressure to maintain the flow from the patched container to the receiving container . Be sure that dry air or dry nitrogen is used to pressure the transfer.

Patched Container Preparation

  1. Check that all the patched ISO container valves are closed and blind flanges are in place.
  2. Remove the blind flange above the red valve of the patched container.
  3. Connect the pressure release line to the red valve outlet. If standard bromine container gaskets are not available then use a new rubber gasket (maximum use time is 24 hours) to ensure a tight connection.
  4. Open the red valve and then the depressurising valve, slowly, to release any pressure that might have developed in the ISO container.
  5. The depressurising line should vent to the absorber scrubber unit.
  6. Remove the blind flange above the yellow valve.
  7. Connect your transfer line to the yellow valve outlet.  If standard bromine container gaskets are not available then use a new rubber gasket (maximum use time is 24 hours) to ensure tight connection. A sight glass in the connection is needed.

Empty Receiving Container Preparation

  1. Check that all the receiving ISO container valves are closed and blind flanges are in place.
  2. Remove the blind flange from the red valve of the receiving container.
  3. Connect this line to the absorber scrubber unit.
  4. Open the red valve on the receiver unit and then the depressurising valve, slowly, to release any pressure that might have developed in the ISO container.
  5. Remove the blind flange above the yellow valve of the receiving container.
  6. Connect the transfer line from the patched container to the yellow valve outlet.  If standard bromine container gaskets are not available then use a new rubber gasket (maximum use time is 24 hours) to ensure a tight connection.
  7. Open the yellow valve on both containeres and all the valves in your liquid transfer line.
  8. Close the depressurising valve connected to the patched ISO container.
  9. Open the pressurising valve very slowly at first to check for bromine leaks.  If b leaks are observed then close the valve and tighted connections as necessary.  If no leaks are observed, then more pressure can be applied to begin the bromine transfer. Use only enough pressure to lift the bromine to the high point in the unloading system (1 atm. pressure will lift bromine about 3.3 meters).
  10. When air/nitrogen blows through the unloading line into your storage tank, the ISO container is empty.  You will recognize this when the transfer line begins to shake.
  11. Close the pressurising valve
  12. Close the yellow valves and then all the other valves in your liquid transfer line.
  13. Close the red valve and then the depressurising valve.
  14. Slowly open the depressurising valve to release the air/nitrogen pressure on the iso-container to your absorber unit.  Wait 5 minutes.
  15. Cautiously disconnect your liquid unloading line from the yellow valve of the receiving ISO container. Replace its blind flange, tightening all the bolts. Do not forget to reinstall the proper gasket.
  16. Disconnect your pressure release line from the red valve of the iso-container. Replace its blind flange, tightening all the bolts. Do not forget to reinstall the proper gasket.
  17. If there has been a bromine spillage, wash it off the iso-container with plenty of water to prevent corrosion. Small bromine spills on the ground may be neutralised with a clear soda ash or a sodium thiosulphate solution. Then dispose of in a manner approved by the local authorities.

Close the cover dome and pin it securely

Realisation: TiDi Graphics