How to splice no-hub cast-iron fittings?
When you need to install a T- or Y-fitting into an existing cast iron pipe, local codes may let you install a plastic PVC fitting into the cast iron and the use PVC pipe and fittings for the rest of the job. But some codes require you to use only cast iron when you are adding to a cast-iron system. Fortunately, cutting into an existing cast pipe and installing a cast no-hub fitting isn't very difficult. Simply first cut an opening for the new fitting; Then install it using neoprene sleeves and banded couplings. Common tools are all that's required.
The tools and materials you will need: grease pencil, snap-cutter or hacksaw, cast-iron no-hub t- or Y -fitting, banded couplings, nut driver.
Step 1: Determine the best location for the fitting, and hold it against the pipe at this point. Mark the top and bottom of the fitting on the pipe, using chalk or a marking crayon. Leave about 1/2 in. of clearance on both marks for fitting room.
Step 2: Cut out the marked section of the pipe using a hacksaw (insert) or a chain cutter. Then install the gasket sleeves onto both ends of the pipe, and slide the fitting and the banded coupling into the opening between the pipe sections.
Step 3: While holding the fitting between the ends of the pipe, roll the neoprene sleeves over the joints at the top and bottom. Mark sure the gaskets are flat; then slide the couplings into place, and tighten the bands.