| Reference Documents | |
| 4WCB-50001 | Perlite for Cold Box Insulation |
| 600.276 | Packing Process Equipment Jackets with Mineral Wool |
| 600.277 | Perlite Loading of Process Equipment Jackets and Field Erected Storage Tanks |
| 685.002 | PH Determination of Mineral Wool (Rockwool) |
| 685.003 | Packed Density Determination of Mineral Wool |
1. General
1.1 All pressure testing needs to be completed.
1.2 Make sure all the construction Quality Assurance and Quality Control checks are done for the piping and vessels.
1.3 The inside of cold box or column shall be clean and dry.
1.4 All heat exchanger plugs shall be removed, number of plugs removed verified against list provided, and the openings stuffed with rockwool before proceeding with perlite, or before the level of rockwool covers them.
1.5 All box and can purges shall be uncovered, and the brass sintered filters attached.
1.6 The insulation must be kept dry at all times.
1.7 Pressurize all lines in box with 5 psig oil-free, dry air. Loss of pressure indicates damage.
1.8 Make sure all thermocouples are checked for continuity before starting.
1.9 Check all thermo-couples for continuity after you have insulated slightly beyond their location, and at the end of the insulation process.
1.10 The contractor is ultimately responsible for repairing rockwool installation if cold spots develop.
2. Perlite
2.1 Valve cages shall be constructed and packed with rockwool before perlite begins.
2.2 Obtain samples of perlite from every truck. Keep perlite in a small airtight container.
2.3 Confirm that the perlite complies with specification 600.277 and 4WCB-50001. Contact the specifier for recommendation of a testing laboratory.
2.4 The inner tank in flat bottom tanks must be pressurized to protect it from collapsing. The specifier or start-up Engineer shall oversee pressurization of inner tank.
2.5 Perlite should be installed to a density of 3.5- 4.5 lb / cu. ft. Discuss with the contractor how they plan on calculating this and the frequency of inspections.
2.6 The contractor should regularly hammer on the sides of the box or can with a rubber mallet to ensure there are no voids near the skin and to promote settlement.
2.7 Due to compaction and settlement, topping off will need to be done after 30 days of operation. Make sure that the contractor has enough perlite on hand or can get some at the end of this period.
3. Preparing for Rockwool
3.1 Ensure certification on rockwool if not Air Products supplied. This must be done through Design Engineering with samples given for every specified quantity packed.
3.2 If Air Products is not supplying the rockwool then test the rockwool in 10-ton increments.
3.3 Make sure the quantities of rockwool available and deliveries are such to prevent running out while packing.
3.4 Some panels on cold boxes are only tack welded and can be removed. The contractor is then responsible for fully welding them on after the installation of rockwool is complete.
3.5 The contractor can take off the removable panels from the cold box and must reinstall them with the proper gasket material when the level of the rockwool reaches the opening location.
3.6 If the contractor wishes to have additional entryways into the cold box, design engineering must be consulted as to the location and additional reinforcing required. Cold boxes with stress skin design have specific field penetration procedures that must be followed.
3.7 Ensure all box openings are sealed daily against elements.
3.8 If the rockwool becomes wet or otherwise contaminated it must be removed and discarded. Do not re-use rockwool that has been exposed to moisture or water.
4. Packing Rockwool
4.1 All people working in the box or column shall wear goggles and a respirator.
4.2 Maintain housekeeping inside box to prevent any combustibles from remaining. The contractor shall keep a log of all items brought in and out of the box.
4.3 All rockwool is to be packed to the density of 225 kg / m3 (14 lb / cu. Ft.) minimum. The contractor should aim for values between 225 and 272 kg / m3 (14-17 lb / cu. Ft.). (A little different from section 9.4 of Doc 600.276. Should 272 be 250?)
4.4 At higher densities the insulating properties diminish and the contractor could run out of rockwool before finishing.
4.5 Packing rockwool with the wrapper still on is not allowed.
4.6 Packing packaged rockwool sections with the wrapper removed is not allowed. Breaking up into fist-sized pieces is required.
4.7 Make sure the rockwool is tightly packed in the region within 2’ of the box or column can walls. Properly packing this area can prevent most frost spots.
4.8 Difficult areas to pack which have caused problems include:Under the cold box frame members Between the tubing outlets on a tubing panel Around pipe and instrument supports
5. Tight areas around piping, valves, and equipment
5.1 Rockwool density should be checked regularly through the shift using the end of a piece of 2 x 4 lumber (Actual measurements 1.5” X 3.5”). Pushing down with one hand should only move the 2 x 4 about an inch down.
5.2 At least once a shift and more frequently at the start of a job or if there are problems, a 1’ x 1’ x 1’ section shall be cut out and weighed to confirm that the proper density is being achieved. Probe with a 2 x 4 first to find the most questionable area.
5.3 Keep a log of quantity packed and depth packed daily and calculate an estimated density. The log is useful to estimate the rockwool needed.
6. QC Documentation
6.1 Density tests of mineral wool and perlite
6.2 Rockwool specification if not Air Products supplied
6.3 Log of bags brought in and height of rockwool
6.4 Log of all items brought in and out of the cold box
6.5 Test analysis results or approval letters of rockwool and perlite