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Step-by-Step Guide to Safely Cutting Ductile Iron Pipes
When working with Ductile iron pipes (DI pipes) in the field, it's essential to follow proper procedures for cutting them. In remote locations, an avoidable mistake could be costly, potentially adding days or even weeks to the project timeline. This article will guide you through the correct method to measure and cut a DI pipe effectively.
Getting Started
Before cutting a DI pipe, it's crucial to choose the right piece. Due to the heating and cooling process during manufacturing, the shape of the pipe may slightly change. Pipes are inspected during manufacturing, and any 14-inch and larger DI pipes marked with green tabs on the bell face are ready for field cutting. These pipes are also "gauged full length," ensuring that the new spigot end will fit properly during installation.
Note: Even if the pipe is marked as gauged full-length, it's still recommended to measure before each cut to avoid potential installation issues.
6 Easy Steps to Cutting DI Pipes
Step 1: Gather the Necessary Tools
Here’s a list of tools you’ll need for cutting DI pipes:
Outside Diameter (OD) tape measure
Chalk, Crayon, or Marking Paint Pen
K-12 Gas Powered Saw with Abrasive Wheel
Angle Grinder
Company-required Personal Protective Equipment (PPE)
Step 2: Pipe Selection
Before making a field cut, ensure the pipe is suitable for cutting as per the guidelines mentioned. For pipes 12 inches and smaller, cuts should be made two feet from the bell face. For pipes 14 inches and larger, look for the green paint tabs on the bell face. These marked pipes should be set aside at delivery for easier identification when a field cut is necessary.
Step 3: Measure the Pipe
Use an OD tape measure and the DI pipe outside diameter chart to measure the circumference and ovality. Check both the horizontal and vertical axis to ensure the OD is within the acceptable range. This ensures the pipe will form a proper seal during installation.
Pro Tip: A Mechanical Joint (MJ) gland can also be used as a gauging device in the field.
Step 4: Mark a Line Around the Pipe
Have a coworker assist in rolling the pipe while you mark a straight line along the pipe using chalk or crayon. Keeping the line straight ensures a clean and precise cut.
Step 5: Make the Cut with the K-12 Saw
Use the K-12 saw to make the cut along the marked line. A co-worker should help roll the pipe while you focus on making the cut straight and safely. This collaborative approach will also allow you to concentrate on operating the saw properly.
Safety Tip: Make sure to wear the necessary PPE, such as leather chaps, welding gloves, steel-toe boots, safety glasses, and a hard hat with a face shield. Your company may have additional PPE requirements, so verify with your supervisor.
Step 6: Use the Angle Grinder to Bevel the Edge
After cutting, bevel the pipe edge to a 30º angle to prevent the gasket from being damaged during installation. For mechanical joints (MJ), you can skip the beveling step and simply remove burrs before installation.
Pro Tip: Although some contractors may use the K-12 saw to both cut and bevel the pipe, McWane Ductile recommends using the appropriate tool for each task.
Tip: The cutting process adds to the overall installation time. On average, you should allow about one minute per inch of pipe—so a 16-inch pipe will take around 16 minutes to cut.
With practice, you'll become more comfortable using the saw and will be able to achieve clean cuts consistently.
Need Assistance With Your Waterworks Project?
Solid offers a wide range of services beyond just manufacturing DI pipe, including estimating, design, production, and installation. We’re committed to providing education and support to professionals throughout the water industry.
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