Class Code 3146
Hardware Mfg; Heat Treating
Class Code 3146 covers businesses that manufacture metal hardware and perform heat‑treating operations. The California pure premium approved for Sept 1, 2026 is $4.079 per $100 of payroll, so accurate classification and loss control matter for your workers' comp costs.
What Class Code 3146 Covers
This classification applies to shops that produce hardware items (bolts, hinges, fasteners, small forgings, lock and key components, stamped parts) and operate heat‑treat processes as an integral part of production. Heat treating includes batch or continuous furnace operations, induction hardening, flame hardening, carburizing or case hardening cycles, annealing, quenching (oil or water), and tempering. Work that is primarily heat treatment of metal parts, including control of atmosphere furnaces, salt baths, or gas carburizing, falls here even when combined with light machining, grinding, or inspection on the same payroll. Light finishing steps tied directly to hardware production are commonly included under this class, but large-scale forging plants or heavy fabrication may fall under different codes.
Who It Applies To
- Independent heat‑treat shops that specialize in hardening small hardware parts
- Manufacturers of fasteners, hinges, locks, keys, and small stamped/forged hardware
- In‑house heat‑treat departments inside hardware or metal parts shops
- Small appliance or tool component shops that perform induction or furnace hardening
- Maintenance technicians who service heat‑treat furnaces and quench tanks
Common Job Duties
- Loading and unloading furnaces, ovens, and salt baths
- Operating induction heaters, gas or electric furnaces, and quench systems
- Setting and monitoring heat cycles, temperatures, and atmospheres
- Quenching parts in oil or water and handling hot parts with tongs/grippers
- Grinding, deburring, and finish machining of hardened components
- Inspecting hardness, microstructure, and dimensional tolerances
- Maintaining and repairing heat‑treat equipment and ventilation
Common Injury Risks
Understanding the $4.079 Rate
The pure premium of $4.079 per $100 of payroll is the portion of premium that statistically pays for expected claim costs for this classification. Insurers multiply that pure premium by your payroll (in $100s) and then apply company underwriting factors — most importantly your experience modification (loss history), policy minimums, and expense and profit loadings — to determine the final premium you pay.
Cal/OSHA Compliance Requirements
Cal/OSHA requires an active Injury and Illness Prevention Program (IIPP) and appropriate hazard controls for heat‑treat shops, including ventilation/exhaust to control fumes and mist, respiratory protection when exposures exceed permissible limits, machine guarding, and lockout/tagout during maintenance. Employers must also implement hazard communication for chemicals (SDS access and training), hot‑work permits where applicable, confined‑space procedures for certain furnaces or pits, and hearing conservation when noise exceeds thresholds.
How Key HR Helps Employers Under Class Code 3146
A PEO like Key HR helps employers in this classification by auditing job classifications, consolidating payroll reporting, and negotiating workers' comp placement based on documented controls. We provide safety program templates, training, respirator and hearing conservation program support, proactive claims management, and return‑to‑work coordination to reduce incurred losses and improve your experience modification over time.
Get a QuoteFrequently Asked Questions
How do I know whether my shop should be coded as 3146?
If your primary payroll is for manufacturing hardware parts and you operate heat‑treat processes (furnaces, induction, quench tanks) as part of production, 3146 is likely correct. If heat treating is subcontracted out, or your primary work is heavy forging or large steel fabrication, a different code may apply. A payroll and operations review — which Key HR can perform — confirms the right classification.
What specific controls will most reduce my claims and premium for heat‑treat work?
Engineering controls (local exhaust/ventilation), strict hot‑work and hot‑material procedures, lockout/tagout during maintenance, proper PPE selection, quench oil management to prevent fire and skin contact, routine equipment maintenance, and formal training and IIPP documentation are highest impact. Consistent injury prevention and early return‑to‑work reduce indemnity costs and improve your experience modification.
If I send parts to a third‑party heat‑treat shop, how does that affect classification and liability?
Work done by a subcontractor is typically not reported on your payroll; the heat‑treat shop reports its own payroll under its applicable code. You should maintain clear purchasing contracts, require certificates of insurance, and verify the subcontractor's workers' comp coverage to avoid vicarious liability and to ensure exposures are correctly allocated.
Quick Facts
- Class Code
- 3146
- Classification
- Hardware Mfg; Heat Treating
- Pure Premium Rate
- $4.079 / $100 payroll
- Effective Date
- September 1, 2026
- Source
- WCIRB Approved Filing
Manage Workers' Comp Through a PEO
Key HR provides pay-as-you-go workers' comp for California employers — no large deposits, no audits, better rates.
Get a Quoteor call (800) 922-4133Ready to Simplify Workers' Comp for Class Code 3146?
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