IS 7556:1988 is the Indian Standard (BIS) for burnt clay jellies. This standard specifies the requirements for burnt clay jallies, which are perforated screens used for ventilation, privacy, and architectural purposes. It covers material, dimensions, tolerances, physical characteristics like compressive strength and water absorption, and methods of sampling and testing. The standard ensures a minimum level of quality for jallies used in building construction.
burnt clay jellies
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
| Parameter | IS Value | International | Source |
|---|---|---|---|
| Compressive Strength (Minimum Average) | ≥ 7 N/mm² | Manufacturer declares from a range of classes (e.g., 5, 10, 15...100 N/mm²) | BS EN 771-1 |
| Water Absorption (Max % by weight) | ≤ 20% (by 24-hour cold immersion) | ≤ 13% for Type FTS; ≤ 7% for Type FTX (by 5-hour boil) | ASTM C530 |
| Dimensional Tolerance (Length/Width) | ± 3% of specified dimension | Defined by tolerance categories (e.g., T2, R1) specifying max deviation in mm, not as a percentage. | BS EN 771-1 |
| Efflorescence | Permissible up to 'Moderate' classification | Classified as 'Effloresced' or 'Not Effloresced' based on a standardized test (ASTM C67). | ASTM C530 |
| Initial Rate of Absorption (IRA) / Suction | Not specified | Specified for some types; e.g., < 30 g/min/30 in² for certain Type FTS units to ensure proper mortar bond. | ASTM C530 |
| Soundness | Should give a clear ringing sound when struck. | Not typically specified as a formal test; soundness is inferred from meeting strength, density, and defect criteria. | BS EN 771-1 |