Stopper Specialists supply Trackable Swabs (also known as Cleaning or Pipeline Pigs) as an advanced method of locating an internal obstruction or blockage of pipes. This technique uses adapted Aqua Foam Swabs and self-contained transmitters called Sondes which are inserted into a cavity inside the Swab.
Blockages are located by pushing the assembly through a pipe until it meets an obstruction; that position can then be determined using a cable and pipe detection locator such as a Cable Avoidance Tool (C.A.T.) by an operator above ground.
The Project
The task at hand was part of a new firefighting project in Wiltshire involving 14 km (8.7 miles) of buried 200mm SDR11 fire main. New firefighting pumps were also to be installed in a designated building with MCC and telemetry controls. A successful completion of the project hinged on the proviso that all pipework must be swabbed and pressure tested prior to final commissioning and handover.
Hidden challenges
With most of the pipework already installed, the challenge for the civils team was to devise a way to successfully swab lengths of pipework up to 1200m long. The task was further exacerbated due to the multiple bends, ductile iron Tees and hydrant branches along the length of the pipeline; factors that would almost certainly impede the Swab’s passage as it travelled through the pipe.
Equipment supplied by Stopper Specialists
After some research, contact was made with Stopper Specialists, a leading Pipe Testing and Flow Control equipment supplier whose method of inserting a Sonde inside a Trackable Swab seemed like a viable solution. An order was placed and the equipment quickly arrived, fully assembled and ready for use. Items delivered included a soft flat-faced Swab with a pocket and a closing plate to insert the Sonde. To enable monitoring of the Sonde from above ground, a model Cat4+ was also included.
Commissioning Engineer, Marc Stephen explained:
“We set up a cross connection from the existing water network and inserted the Swab into this location for each operation. We utilised the existing water network to push the Swab around the pipework by cross connecting from an existing hydrant to another hydrant on the new fire main and then operated strategic hydrants along the pipework to draw the Swab through the system until we got the end test plate for removal.”
Getting the job done…
Stopper Specialists helped us overcome significant problems encountered with the Swab having trouble negotiating the bend in the ductile iron Tees. This was overcome by using a chamfered Swab replacement and cutting a hole in the backing plate to insert and seal the Sonde in place. Using this approach, all swabbing operations were then completed successfully in one operation.
This method considerably reduced the time that would have been spent relying on the traditional method of monitoring the volume of media in the pipework and waiting at the final location for the Swab to arrive.
Some final thoughts from Marc…
“We had previously lost Swabs due to numerous hydrant branches from the main pipework and the Swab turning into them. If a Swab is lost then it requires the hydrants to be laboriously opened in sequence to locate the one with reduced flow. This would have meant installing a cross connection and then pushing the Swab back into the main branch before we could continue with the works.
The Swab replacement meant detecting and following its path was easy as we already had the pipework routes mapped and therefore could easily utilise the Cat4+ detection locator provided by Stopper Specialists.”