PIPE FREEZING NEED TO KNOW INFORMATION
You the Contractor (the person/company awarding this work) should copy this page and send it to your field operations person. It has pertinent information for them which they should have prior to the scheduled pipe freeze. If “Alerts” were included with your proposal, they too should be copied and sent to the on-site field person(s).
The below pertains to ALL Freeze Jobs –
Contact us @ 305-233-8728 or WatersMechanical@gmail.com
· Nitrogen Delivery - The Liquid Nitrogen Dewar(s) will be sent to the jobsite 1-2 day(s) prior to the scheduled freeze. The contractor or owner is responsible for receiving the Dewar(s) and placing them near (20' or less) the actual freeze jacket location. Dewar(s) weigh approx. 600 lbs. WMI will provide a cart for your use when we arrive.
o Note - We cannot control the time of delivery from the liquid nitrogen vendor to your jobsite – If you do not have personnel on site each day; then be sure to plan for a Tech or someone to be on site all day on the date the nitrogen is supposed to be delivered. If there is no one to sign for the product then it will not be dropped off. The work will have to be re-scheduled and the liquid nitrogen that was not received will be charged for as it does not store and is not refundable.
· Paint and Insulation – Paint and/or insulation must be removed from the piping by the contractor or owner at the location where the freeze jacket is to be placed. The pipe must be cleaned around its whole circumference. The minimum length will be listed on the proposal (approximately 3 x the pipe diameter)
· Timing of a Shutdown - Systems which are low temperature such as chilled water or glycol based are to remain in operation until all the freeze jackets are set up and ready to be turned on. Shutting down the system prematurely can cause temperature changes which may adversely affect freeze times and liquid nitrogen consumption. PLEASE discuss any shutdown plans with WMI prior to us scheduling your work.
· Hot Work Permit - After the piping work has been completed, pressure testing is recommended. After testing, the ice plugs will be thawed using an acetylene torch. If a Hot Work Permit is required, it is the contractor’s responsibility to acquire one. If the fire system is to be put in test; it is the responsibility of the contractor to make arrangements with the owner to do so.
· Ice Plugs must be at least 10 pipe diameters away from nearest tee or branch connection in order to keep system on line. Closer than 10 pipe diameters may require shutting down pumps to obtain the freeze and may need to remain off for completion of work. Consult with WMI anytime this criterion is not possible.
· All flow must be stopped (at freeze point) in order to obtain an ice plug! Valve(s) can be closed downstream to make flow static - Or - pumps must be shut down. Once ice plug is obtained system operation can resume.
· There must be a gauge port or vent in the section of pipe which is to be isolated. If not existing, then WMI will field tap (No Charge), Contractor to weld in 1/2" T-O-L (supplied by WMI) or a temporary clamp on tap will be used if applicable.
· Cutting and Welding can be executed very close to the freeze point(s). However, hammering and impact guns are not permissible for use on piping which is frozen or connected to piping that is frozen.
· Concerning threading operations, installing and removing threaded fittings on frozen pipe. A proper back up when removing or installing fittings is required as not to stress the pipe where there is an ice plug. For threading with a power threader, the proper support arm must be used with the power threader.
· Pressure testing completed work (strongly recommended) - Note that ice is porous and we limit gas testing to 60 PSIG. If the ice plug is covered by the system’s fluid where the ice is not directly exposed to the compressed gas; then pressure tests are permissible up to 600 PSIG. For any system requiring a pressure test higher than 600 PSIG, consult WMI with your MOP and requirements.
· Thawing ice plugs - After work is completed and pressure tested (or not tested); then the ice plugs are thawed. Should a problem arise (eg. leaks) WMI cannot close the ice plug without completely restarting the entire freeze process. If there is a substantial leak in the new repair or valve, it will not be possible to re – establish an ice plug the due to flow.
· On completion (usually during our breakdown and thawing process) you the contractor are responsible for moving the liquid nitrogen Dewar’s back to the loading dock or other designated staging area for pick up. Please take advantage of our DEWAR CART which our Techs have with them to move the Dewars back to the loading dock. Unless specific arrangements are made ahead of time the Dewars are normally picked up by the vendor 1-3 day(s) after completion of the work.
You can submit a request for a quote by filling out our online questionnaire or by downloading a questionnaire. If you download a questionnaire, complete the form and email it to WatersMechanical@Gmail.com. If you any questions regarding how request a quote, please do not hesitate to call us at 305-233-8728.