The backing plate shall be coated with a parting agent to facilitate removal from the applied refractory. Test panel refractory shall be installed by pneumatic ramming in a manner simulating the actual installation in other words, sidewall or overhead. After refractory installation is completed, the test panel backing plate shall be removed immediately and examined for consolidation and voids.
No additional test specimens and testing are required as long as material qualification results and applied refractory workability is satisfactory e.
Satisfactory results will serve to qualify the equipment, techniques, and applicator. No applicator shall ram pack refractory materials until he or she has been qualified. Examination of the Sectioning or breaking of the panel is panel may be performed immediately after permitted 18 hours after completion of the ramming, or within 24 hours, as directed panel unless otherwise directed by the by the owner.
Scheduling of Material Qualification Tests and delivery of those materials and test results to the site. Scheduling and execution of work to qualify all equipment and personnel needed to complete installation work, including documentation and verification by the inspector.
Preparation and identification of all testing samples and timely delivery to the testing laboratory. Advance notification to the owner of the time and location where work will take place so that this information can be passed on to the inspector.
Hydraulic bonded, castable refractories shall be packaged in moisture- roof bags with the product name, batch number, and date of manufacture clearly shown. Chemical setting refractories shall be packaged in heat sealed plastic to assure vapor-tight enclosure.
Mechanical protection shall be provided by cardboard, rigid plastic, or metal outside containers. Each container shall be marked with the production batch number. Packages with broken seals or variation in workability shall be subject to requalification. Refractory materials shall be stored in a weather-protected area. Time limits for material qualification tests see 4. Water used for mixing in the refractory shall be potable. Pre-wet the refractory by mixing with water prior to charging into the gun to reduce dusting and segregation, while at the same time avoiding plugging in the feed hose.
Optimum amount and mixing of the pre-wetted material shall be per the applicator qualification testing. Gunning equipment shall provide a smooth and continuous supply of water and material without causing laminations, voids, or rebound entrapment. Shotboards or perpendicular edge cuts shall be used to terminate work areas. When stoppages greater than 30 minutes are encountered or initial set is determined by the inspector, only full thickness lining shall be retained.
Start gunning at the lowest elevation, building up the lining thickness gradually over an area of not more than 10 ft2 1 m2 to full thickness and working in an upward direction to minimize the inclusion of rebound. Rebound material shall not be reused.
Downhand gunning beyond 30 degrees below horizontal is prohibited unless agreed to otherwise by the owner. The refractory shall be placed by an alternative placement technique such as casting, hand packing, or repositioning to avoid the downhand orientation.
Shot board height and depth gauges shall be used for thickness measurement guides. After gunning and confirmation of sufficient coverage, the refractory shall be trimmed cut back in a timely manner with a serrated trowel or currycomb. Cut back shall be performed when the surface is not damaged by the cut back techniques, and before initial set occurs.
Forming shall be sufficiently strong to support the hydraulic head of wet refractory that it will retain and to resist any mechanical loads, such as vibration. The forms shall be waterproof and leak free. Dimensional tolerances shall meet specified requirements. A release agent such as grease, form release, or wax shall be used to facilitate stripping of the forms.
Refractory shall be mixed using procedures, equipment, and water levels demonstrated in material and applicator qualification tests. For vibration casting in pipe sections, mixer capacity should be sufficient to facilitate placement with no more than 10 minutes between successive mix batches. For pump casting, mixer capacity shall be sufficient to allow for continuous pump operation without stops and starts to wait for material. For vibration casting, two or more rotary vibrators shall be mounted externally on the equipment or component to be lined.
Vibrators shall have adequate force to move and consolidate the material being vibrated. Each vibrator shall be independently controlled to focus vibration and prevent segregation due to over vibration. For pouring or pump casting, submersion vibrators or rodding may be used to aid refractory flow and filling of the formed enclosure.
Curing shall be per 6. All air-setting phosphate bonded refractories shall be mixed in a rotating paddle mixer, such as those manufactured by Hobart. The mixer shall have steel paddles and bowls. Aluminum paddles and bowls shall not be used due to their potential to react with the acid component in the refractory. All heat-setting plastic refractories shall be installed at the manufactured consistency.
Field water addition or reconditioning is not permitted. Any reconditioning must be performed by the manufacturer under controlled plant conditions, and the reconditioned material shall be fully requalified per 4. The manufacturer shall measure the workability index on plastic refractories per ASTM C seven days after manufacture and provide this to the contractor.
The manufacturer shall also provide the minimum workability index for each plastic refractory supplied, for suitable installation. During placement, refractory shall be fully compacted in and around the anchor supports to form a homogeneous lining-structure free of voids and laminations.
Once consolidated, overfill shall be removed flush with the tops of the hexmesh or hexalt anchors using a trowel or currycomb. The surface shall then be tamped, as necessary, to remove imperfections such as surface tearing and pull away defects. Water slicking of the lining surface is not permitted. Water used to clean and lubricate tools shall be dried off prior to use on the refractory. This work surface shall be maintained to avoid contaminating fresh refractory with dried-out material from previous cutting or separating operations.
Refractory shall be ram packed in successive handful sized clumps using a handheld, reciprocating pneumatic rammer, fully consolidating each clump into a uniform mass and compacting the material in and around the anchor supports to form a homogeneous lining structure free of voids and laminations that is greater than the desired lining thickness.
Once placed and consolidated, the lining shall be trimmed to the desired lining thickness using a trowel or currycomb. Cutback material may be reused if workability characteristics are not diminished. Under no circumstances shall dry or crumbly material be installed. The trimmed surface shall then be tamped, as necessary, to remove imperfections such as surface tearing and pull away defects.
Metal fiber reinforcement shall be used only when specified by the owner. Fiber additions shall be uniformly dispersed in the castable without agglomeration. The procedure for adding metal fibers during lining installation shall be as follows: 1. Load castable into mixer and pre-mix. Add pre-wet or mixing water. Specific details of fiber dimensions, concentration, and metallurgy shall be covered in documentation per 4. Advance agreement with the owner on all installation details as defined in 4.
Execution of installation work, including preparation of as-installed samples per 5. Inspector verified documentation of installation records, including these: 1. Product s being applied. Pallet numbers and location where applied. Fiber and water percentages. Mixing details including time, temperature, and aging time if gunned. Location and identity of samples taken for installation quality control. Accountability for installed refractories meeting specified standards, including as-installed testing results as defined in 5.
Fiber additions shall be performed during manufacture of the castable or plastic refractory. Additional applicable standards and other documents are listed in the bibliography that follows the Annexes. ACI1 , Refractory Concrete edition. NOTE The biscuit has the shape of the enclosed area and the thickness of the lining. Biscuits are normally independent of each other except for limited connections through perforations in the anchoring system.
NOTE For hydraulic bonded castables, curing occurs at room temperature and is facilitated by an excess of water being present to react with the cement component. For phosphate bonded plastic refractories, heating to F to F C to C is required to form the bond. It is usually expressed either in grams per cubic centimeter, or in pounds per cubic foot. Moisture shall be directed away from the refractory 7. If the manufacturer's shelf life recommendations e.
Discarding Criteria Materials that exceed the shelf life see 7. Packaging and Marking 7. Chemical-setting refractories shall be packaged in heat-sealed plastic to assure vapor-tight enclosure Mechanical protection shall be provided by cardboard, rigid plastic, or metal outside containers.
Each alloy anchor shall be stamped or laser etched or supplied in sealed traceable packaging to identity alloy and forming manufacturer. Each unmarked sheet shall be confirmed by PM before installation. Selection, instalation, inspection, and testing of anchors shall be in acoordance with the design drawings and specifications, 8 Qualification and Testing 8. Testing and Test Procedures 8. The laboratory conducting the test procedures shall be subject to aucit and approval by the owner.
Quality control testing shall consist of density, cold crushing strength CCS , permanent linear change PLC , abrasion loss when applicable , and workability index Plastics only , Other tests required by the owner shall be as defined in the owner's specifications. For specimens cut from a larger cast panel, an open face shall not be used for the top or bottom ie, load application faces during the test. New shims shall be used for each test cube. Shim dmersions shall be approximately 3 in.
Two thinner shims making up the same total thickness may be used in piace of a single shim, Testing machine minimum sensitivity and maximum loading rate shall be as in Table 2. Weigh the specimens to the nearest 0. Caloulate and report the amount of refractory lost by abrasion in cubic centimeters to the nearest 0. Testing procedure shall be as follows, a Measure specimen dimensions to the nearest 0,02 in, 0. The Index shall be based on single-layer linings 5 in.
Modifications to account for greater thickness. NOTE See foctnetes atthe end ofthis annex for the source of the definition. Adetional definitions are contained in Section 3. Refractories consisting essentially of alumina and silica, such as high-alumina, alumina-zirconia-silica: Refractories containing alumina-zirconia-slica as a fusion cast body or as an aggregate used in erosion-resistant castables and precast special shapes.
Also called a jack arch, arch, sprung "'; In furnace construction, a bowed or curved structure that is supported by abutments at the sides or ends only and that usually spans an opening of srace between two walls, arch, suspended 1; A furnace roof consisting of brick shapes suspended ftom overhead supporting members. C-clip anchors '"; A C-shaped metallic anchor used to attach ceramic anchors to the casing or shell of process: unit or fired heater catalyst "!
Originally, the term ceramics referred only to ware formed from clay and hardened by the action of heat and to the art of making such ware. However, its significance has gradually been extended by usage, and it is now Understood to include all refractory materials, cement, lime, plaster, pottery, glass, enairels, glazes, abrasives, electrical insulating products, and thermal insulating products made from clay or from other inorganic nonmetallic mineral substances.
These refractories include phosphate-bonded Plastics and ramming mixes. Specific gravity 4. Hardness 8. Speoific gravity is Cristobalite is an important constituent of silica brick crown "1: A furnace roof, especially one which is dome-shaped; the highest point af an arch.
Typically, this would consist of a low-density insulating refractory behind a stronger, medium, or high-density refractory, dusting 1": Conversion of a refractory material either wholly or in part into fine powder or dust.
Dusting usually results from a chemical reactions such as hydration or b from mineral iriversion accompanied by large and abrupt change Involume, such as the inversion of beta to gamma dicalcium silicate upon cooling, emissivity, thermal: The capacity of a material for radiating heat, commonly expressed as fraction or percentage of the ides!
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