Heritage Cases

The activity involves the replacement and upgrade of sewer pipes using pipe cracking method. Pipe Cracking Method Explained a) Preparation • HDPE pipes on will be inspected for defects. • All house connection along the section will be identified from design maps and on preconstruction CCTV footage and reports. • Sewer pumps (with standby pumps) will be tested, and hoses inspected for leaks. • Excavation for launch and receiving, and house connection will commence. • HDPE pipes will be butt welded to the required length b) Pipe Cracking Sequence • When butt welding and excavation is complete, the manholes, upstream and downstream of the section will be plugged and over pumping will commence. • Existing sewer pipe will be cut at house connections and the sewer from affected houses will be blocked. • The newly butt-welded HDPE pipe will then be pulled through to replace the existing pipe. • As soon as the whole length has been pulled through, the HDPE pipe will be cut at house connections and the HDPE Y-Junctions will be jointed for house connections using the electrofusion method. • Air testing will be conducted in accordance with Clause 7.2 of SANS 1200LD. No water level drop will be allowed for these types of joints, as they are expected to be airtight. • On acceptance and approval, house connections will commence. Bedding and backfilling will be done on launch and receiving pits, and on house connections. • Compaction tests will be done on the bedding and on backfill. • On completion, post CCTV inspection will be conducted and a report will be submitted to the Employer