Hot Tapping
UNDER PRESSURE DRILLING (' Hot Tapping ')
Client 1.
A plastics manufacturer was expanding its factory capacity and consequently needed to extend the existing services. The only system that could not be isolated was the process water flow pipe, and as the factory runs 365 days of the year, the client was reluctant to arrange a shut down just to install a 6" branch on the 10" main.
The accepted method was to under pressure drill a valved branch, from which the new system could be connected.
Client 2.
A utilities subcontractor was installing water test equipment. Each unit required a flow and return circuit from the main. The water main at this location was asbestos cement and it was noticed that there was some damage to the pipe. Two regular under pressure tees would have left the damaged section of the pipe exposed. The design of the under pressure tee was therefore made longer in order to act as a repair clamp to the damaged area of the pipe, as well as having two branches at the required 12" centres.
The branches were both under pressure drilled, flushed to clear any debris from the system and the new connections made.
This application shows a double branch specifically fabricated to continuously draw off samples of water, run it through an optical test unit, and then return it to the main without loss or contamination.
Client 3.
National Health Service
We have, through our clients, successfully completed numerous under pressure valved branch installations in both National Health Service and Private hospitals on heating, chilled/cooling water and domestic hot and cold water services.
In all the above cases the under pressure drilling method was chosen, as the work could be carried out without having to disrupt the day to day running of the departments, and more importantly without the need to shut any of the systems down. In all but one application, which was in a 24 hour a day used corridor, no disruption was caused to the continual operation of the areas in which we were working.
