erobin
Chemical
- Jun 27, 2007
- 1
We have a consultant who is recommending fusible plugs for tank jackets in a fire case to drain the liquid out of the jacket prior to it reaching its boiling point because the existing valves aren't sized for 2 phase flow.
I have several concerns about fusible plugs while I admit the valves are probably not large enough for 2 phase flow. The valves were originally sized for all vapor flow which has been the industry standard.
- Plugs aren't in the ASME Pressure Vessel Code.
- You have to locate the plugs near the bottom of the vessel so if you have a fire in one room you could drain the cooling water for the entire building on to the floor of that room.
- Plugs have an unknown maintenance requirement. One website recommends replacing them every year. That could mean draining all of the cooling water system to do the replacements.
- Plugs can become corroded on the inside or outside and fail to operate.
I've talked to the manufacturer of the fusible plugs and they said Bayer and Dow use fusible plugs for this type of service.
What does anyone else think? Any experience with fusible plugs? We would still have the valves on the jackets so they are protected by ASME devices.
I have several concerns about fusible plugs while I admit the valves are probably not large enough for 2 phase flow. The valves were originally sized for all vapor flow which has been the industry standard.
- Plugs aren't in the ASME Pressure Vessel Code.
- You have to locate the plugs near the bottom of the vessel so if you have a fire in one room you could drain the cooling water for the entire building on to the floor of that room.
- Plugs have an unknown maintenance requirement. One website recommends replacing them every year. That could mean draining all of the cooling water system to do the replacements.
- Plugs can become corroded on the inside or outside and fail to operate.
I've talked to the manufacturer of the fusible plugs and they said Bayer and Dow use fusible plugs for this type of service.
What does anyone else think? Any experience with fusible plugs? We would still have the valves on the jackets so they are protected by ASME devices.
