Sewer Mandrel Inspections
When you’re in the excavation business, especially working on underground utilities, timing and precision are everything. One of the most crucial steps in sewer main installations is passing the mandrel inspection. For those unfamiliar, a mandrel is a device that helps check if your sewer pipe is round and has maintained its shape after backfilling. The stakes are high—if it doesn’t pass, you’re looking at significant delays and rework.
Here's a real-world scenario we faced: we had a mandrel inspection scheduled for 1:00 PM, but we dropped the ball and missed it. The inspector graciously waited, and we had to rush to get the job done right. These situations happen, but it’s important to know how to handle them.
What is a Sewer Mandrel?
A mandrel is a metal football-shaped tool used to verify that your sewer pipes haven't become distorted during installation. It’s a simple but effective way to ensure that the pipes are up to standard. The goal is for the mandrel to pass through the pipe easily. If it doesn’t, it means the pipe is deformed and requires attention.
Steps to Handle a Sewer Mandrel Inspection
Communication is Key: This is where we stumbled. Always ensure that everyone on the crew knows when the inspection is happening and who is responsible for being on-site. We had a last-minute scramble because of miscommunication, and it almost cost us the job.
Have the Right Equipment: For this inspection, you’ll need more than just a mandrel. In our case, we were missing a blower fan, so we improvised by using a leaf blower to send a string down the line before pulling the mandrel. It’s always a good idea to have all necessary tools ready ahead of time to avoid delays.
Test the Pipe's Integrity: After backfilling, the pipe can sometimes become compressed or misshapen. The mandrel is used to check this. Tie the mandrel to a string and pull it through the pipe. If it passes through easily, your installation is good to go. If not, you’ve got some work to do.
Adapt When Necessary: In our case, we started by blowing the string uphill, but it kept getting caught. So, we switched to the downhill side and were able to get it through without an issue. Sometimes things don’t go as planned, but being able to adapt and think on your feet is crucial.
Keep the Inspectors in the Loop: Inspectors are human, too. If you’re running behind, let them know. Most of the time, they'll appreciate the heads-up and may be willing to wait, as ours did. Building good relationships with inspectors can go a long way in situations like this.
Pass the Test and Follow Up: Once we passed the mandrel test, we immediately communicated with the team and the client, letting them know the job was good to go. This keeps everyone informed and helps maintain trust with your clients.
Lessons Learned
This project reminded us of a few key points: always be prepared, communicate clearly with your team, and have the right tools for the job. Sewer inspections, especially mandrel tests, can make or break a project timeline, so it’s crucial to be on top of everything.
At Sy-Con, we handle underground utilities with precision, whether it’s sewer mains, storm drains, or water lines. We know what it takes to get the job done right—no shortcuts, just hard work and experience. Ready to get your project started? Contact us today to start.
