Specification for door handles for mortice lock (vertical type)
1975 Edition

IS 4992 specifies various materials for door handle components as follows:

• For the handle housing: cast brass with minimum 2 mm thickness and copper content not less than 60% (IS: 292-1961, Grade 3), brass sheet at least 1.25 mm thick with CuZn 40 alloy (IS: 410-1967), mild steel sheet with minimum 1.25 mm thickness and tensile strength not less than 32 kgf/mm² (IS: 1977-1969, Grade St-32-0), aluminium alloy pressure die castings of minimum 2 mm thickness (IS: 617-1959, grades A-5-M or A-6-M), aluminium alloy sheets with 1.25 mm thickness (IS: 737-1974), aluminium extruded sections (IS: 733-1967), and zinc base alloy die castings with at least 2 mm thickness (IS: 742-1966).

• For handles or knobs: materials similar to the housing are specified including cast brass, aluminium alloys, and zinc alloy die castings.

• Finishing includes natural or bright electro-chromium plating for brass, anodized coating for aluminium alloys (minimum Grade AC 10 as per IS: 1868), and bright chromium plating for zinc alloys and mild steel.

These specifications ensure robustness, corrosion resistance, and aesthetic appeal.

Durability testing under IS 4992 involves:

• Selecting one handle out of every 100 produced and fitting it onto the corresponding mortice lock.
• Operating this handle through 1,000 complete cycles to verify there are no damages or functional failures.
• Applying a horizontal force of 100 kg at the handle’s extreme position to ensure it remains free from cracks or permanent deformation.

Furthermore, handles undergo inspection for manufacturing quality, dimensional conformity, and performance. Any deviations or failures render the handle non-compliant. These tests confirm the handle's capability to endure repeated use and mechanical stresses.

Each door handle must bear clear markings including:

• The manufacturer's name or trademark.
• The year the handle was produced.
• Country of origin.

Additionally, the handle may optionally display the ISI certification mark, indicating adherence to Indian Standards and quality assurance under ISI supervision.

Packaging boxes should be marked with the manufacturer’s identification, quantity contained, country of origin, and manufacture year to ensure traceability and quality control throughout the distribution chain.

According to IS 4992, a batch (lot) of door handles is accepted if the number of defective units in the sample does not exceed the permissible defect count specified in Table 2 of the standard. Defects include failures in manufacturing quality, construction, dimensional accuracy, or performance tests such as operational endurance.

The sample sizes and defect thresholds vary according to lot size, for example:

• Lots up to 100 units require sampling 5 handles with zero defects allowed.
• For 301 to 500 units, 20 samples are tested, permitting a maximum of one defective handle.
• Larger lots have correspondingly larger sample sizes and higher acceptable defect counts.

Handles must also be free of visual defects, and any sharp edges must be removed to meet workmanship standards.

Yes, IS 4992 specifies finishing treatments depending on the handle material:

• Brass handles should have either a natural finish or be bright electro-chromium plated to provide corrosion resistance and aesthetic appeal.

• Aluminium alloy handles must be anodized to at least Grade AC 10 quality as defined in IS: 1868-1968, which enhances surface hardness and corrosion resistance.

• Handles made from zinc base alloys and mild steel require bright chromium plating to ensure durability and a polished appearance.

These finishing standards are intended to maintain the functional and visual quality of the door hardware over time.