This 1988 standard outlines the specifications for burnt clay perforated blocks known as jallies, detailing their dimensions, quality criteria, and testing protocols. It serves as a guideline for manufacturers, engineers, and quality inspectors to ensure these decorative clay elements meet strength, durability, and aesthetic standards for architectural use.
Overview
This 1988 standard outlines the specifications for burnt clay perforated blocks known as jallies, detailing their dimensions, quality criteria, and testing protocols. It serves as a guideline for manufacturers, engineers, and quality inspectors to ensure these decorative clay elements meet strength, durability, and aesthetic standards for architectural use.
Audience
Contents
Structure
This section defines the applicability of the standard covering dimensions, tolerances, and terminology referencing IS 2248-1981. It also outlines rounding rules according to IS 2-1960 and provides permissible dimensional variations based on measurement of multiple units.
All terminology used is aligned with IS 2248:1981, while test results are to be rounded as per IS 2:1960 guidelines. Thickness and void area specifications are detailed in Clause 3.3, ensuring consistency with international practices adapted for Indian conditions.
Sets out the allowed dimensional tolerances for jallies across specified size ranges, with tolerances based on measurements from a minimum of 20 samples. Compliance with rounding standards is emphasized to maintain manufacturing uniformity.
Highlights rounding off rules, international coordination, and key dimensions for bonding features, accompanied by a summary of dimensional tolerances to ensure product quality.
Describes specimen preparation, dimensional limits, and the method to determine breaking load via vertical support and application of uniform load at specified rates, along with reporting requirements.
Specifies sample sizes and sampling procedures as per IS 5454-1978, along with instructions for averaging absorption results and rounding off final test values in compliance with IS 2-1960.
Details mandatory marking elements including manufacturer’s name and jalli type, the optional use of BIS Standard Mark under licensing regulations, and rounding protocols for test data.
Explains the test setup and process to measure breaking load per unit width, specifying the minimum average load requirement and formula for calculation based on multiple specimens.
Outlines specimen drying, immersion, weighing steps, calculation formula for water absorption percentage, and the maximum acceptable limit to ensure durability.
Describes the soaking, drying cycles, environmental conditions, and evaluation criteria for efflorescence with acceptable limits not exceeding slight deposits covering 10% of surface area.
Frequently Asked
The standard sizes for burnt clay jallies include various rectangular dimensions such as 190x190 mm, 190x140 mm, 140x140 mm, 140x90 mm, and 90x90 mm with thickness options of 50 or 100 mm. Permissible dimensional deviations depend on size, generally ranging from ±12 to ±40 mm as per measurement of at least 20 units, ensuring consistent manufacturing quality.
Clay used for jallies must be suitable for molding and firing to yield durable, crack-free products with uniform color and texture. It should be free from free lime nodules to prevent defects and possess adequate plasticity and low shrinkage to minimize warpage, typically not exceeding 3%. These properties collectively contribute to the production of robust, aesthetically consistent burnt clay jallies.
Breaking load is assessed by supporting the jalli specimen vertically on cylindrical steel beams and applying a perpendicular load at a steady rate until failure, following the procedure in Appendix A. The average breaking load must be at least 12 Newtons per millimeter of specimen width to satisfy the standard’s strength criteria.
The average water absorption of burnt clay jallies should not exceed 15%, as determined by the water immersion test described in Appendix B. This limit ensures adequate resistance to moisture ingress, supporting the longevity and durability of the jallies in construction applications.
Efflorescence testing involves immersing jallies in water, drying them twice in controlled warm conditions, and examining the surface for salt deposits. The acceptable rating is 'slight,' where no more than 10% of the total surface area is covered with a thin layer of efflorescent salts, ensuring visual and structural integrity as per the standard.
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