BIS Seeks Public Feedback on Revised Standard for Sulphuric Acid
India’s Bureau of Indian Standards (BIS) has announced a public consultation on the revised standard for sulphuric acid, inviting feedback from stakeholders until February 1, 2025. The existing standard, which was first published in 1950 and revised three times, is undergoing a major update to align with international chemical safety specifications.
Aligning Standard with ISO Specifications
The revised draft includes references to the International Standards Organisation (ISO) specifications, ISO/910-1977 and ISO/R 915-1968, to ensure global consistency and safety. Sulphuric acid, a highly reactive and widely used industrial chemical, has been categorized into four different grades, each with its own specific use and purity requirements.
The four grades outlined in the revision are:
- Technical grade (Tech): A liquid not darker than brown in color.
- Battery grade: Includes two sub-grades – concentrated and dilute. Both are colorless liquids with strict purity requirements for suspended matter and visible impurities.
- Chemical Pure (CP) and Analytical Reagent (AR) grades: Clear and colorless liquids, free from suspended matter and impurities. These grades can be supplied in more dilute or concentrated forms, as agreed upon between buyers and suppliers.
Enhanced Safety and Quality Standards
The draft standard also introduces maximum permissible limits for heavy metals and chlorides in sulphuric acid, aiming to ensure higher safety and quality standards. The key specifications for each grade are listed in the table below:
| Parameter | Tech Grade | Battery Grade (Concentrated) | Battery Grade (Dilute) | CP Grade | AR Grade |
| Iron (% by mass, max) | 0.01 | 0.003 | 0.001 | 0.001 | 0.00005 |
| Chlorides (% by mass, max) | – | 0.001 | 0.0003 | 0.0035 | 0.00002 |
| Heavy metals (as lead, % max) | 0.005 | – | – | 0.002 | 0.0001 |
| Arsenic (% by mass, max) | 0.004 | 0.00012 | 0.00004 | 0.00002 | 0.00005 |
| Selenium (% by mass, max) | – | 0.002 | 0.0006 | – | – |
| Copper (% by mass, max) | – | 0.003 | 0.001 | – | – |
| Zinc (% by mass, max) | – | 0.003 | 0.001 | – | – |
| Nitrates (% by mass, max) | – | 0.003 | 0.001 | 0.003 | – |
Packaging and Labelling Requirements
To ensure safety during transport and storage, the draft also specifies the types of containers suitable for each grade of sulphuric acid. These include polyethylene containers, screw-stoppered stoneware bottles, glass carboys, and cans. For CP and AR grades, the containers must be fitted with Teflon washers and stoppered with HDPE or other suitable stoppers.
Additionally, containers of up to 12 liters must be clearly marked in red letters with important information, including the name and grade of the substance, the manufacturer’s details, net weight, lot number, expiry date, and a prominent warning: “CORROSIVE, HANDLE WITH CARE.” For larger containers, such as drums, the red lettering should be at least 5 cm in height.
Call for Stakeholder Feedback
BIS is calling on manufacturers, industry experts and stakeholders to review the draft and provide feedback to ensure the revised standard is consistent with current practices and international norms. The consultation period is open until February 1, 2025.
The full text of the revised standard for sulphuric acid can be found here.
We acknowledge that the above information has been compiled from Bureau of Indian Standards (BIS).
