O.T.H. Supervisor Check List

The following is a list of checks and observations that can be periodically performed during an O.T.H. Install. These checks and observations may help your Mixer Operator realize and resolve equipment issues during the install process. Assigned technicians must immediately address and resolve a discovered issue to ensure that mixing equipment is operating properly before injecting into a liner. This may involve halting the pumping process, pulling the stinger/ hose out, and pumping into waste drums while trouble shooting until the proper catalyst/resin mix is produced.

Pre-Pump:

• Before each pump the mixer operator will perform a “Purge Pump”. This will be 100lbs + resin pumped into a waste drum. The purpose of a Purge Pump is to visually check the resin mix BEFORE it is pumped into a liner. As well, any issues like dispense hose gurgling or catalyst/resin pressure spikes will reveal system clogs and other immediate problems. It is important that a competent person or supervisor is assisting the mixer operator with a purge pump before injecting into the liner.

• On the 1st pump of an install the mixer operator should perform a gel test taken from their purge pump. This will ensure that resin mix is kicking off within the desired time frame. The mixer operator can make adjustments here to the catalyst/resin rates before injecting.

•Yields

Each slug pumped will produce a yield of pounds pumped/ footage liner wetout. Before each pump your mixer operator should have a yield produced from the last slug. Yields should match up relatively closely with the yield provided on the Wetout Sheet. If yields are too high or too low, adjustments to pinch roller gap may be required.

Mid-Pump:

• At any time during resin injection the resin mix can be visually inspected. Ask the mixer operator for a cup sample. The cup sample produced should be a consistent light blue color

•If resin is swirled, deep blue, or brownish in color stop injection and have operator trouble shoot until mix is consistent. Do not resume injection until catalyst/ resin mix is consistent light blue

•During injection crew members should visually inspect resin slug and immediately report any swirls or color changes.

•Ask mixer operator if catalyst/ resin rates and pressure is consistent. Consistent catalyst/resin rates and correct pressure readings indicate a clog-free properly operating mixer.

•Ask the mixer operator about resin temperatures. Injectable resin temperature is always 70°F-75°F. If resin is still above appropriate temperatures during resin cooling process, additional circulation through heat exchanger will be necessary until appropriate temperature is reached.

• Ask the mixer operator about Gel Test Times.

Average gel test times should kick-off in the 4:30min range. For hot weather installs, the mixer operator should adjust catalyst/resin rates so that gel tests kick off in the 5:00-5:30 min range. During hot weather installs, if gel tests seem to be kicking off fast mixer operator will need to make adjustments. If the catalyst/resin mix is too “hot” for ambient temperatures the liner is at high risk of premature kick off.

Post pump:

•Perform a slug inspection at the end each pump. Take note of any inconsistencies. Lack of solid light blue solid color in the resin slug will alert the mixer operator to any issues that need immediate attention.

•Dark spots:

If any dark blue spots appear in the resin slug they may be possible “hot spots” of a high catalyst concentration. These hot spots are to be attended to and constantly iced while sitting on the roller beds until this portion of liner is submerged in the down tube.

• Pump/ hoses:

During hot weather installs, all resin hoses and pumps should be covered and shaded. After each pump the dispense hose will contain residual catalyzed resin. It is important to ice down the dispense hose here to keep it from kicking off. To be extra cautious, the mixer operator can blow down their dispense hose with acetone