StandardsWhat are FO CI and HI safety boots

What are FO CI and HI safety boots - Complete Guide 2026

7 min readStandards

Quick Summary

SRC is the highest slip resistance classification for safety footwear under EN ISO 20345. SRC certified footwear has passed both SRA and SRB slip resistance tests, providing reliable protection agains.

Understanding Special Protection Markings

FO, CI, and HI are special feature markings on safety boots under EN ISO 20345. These markings indicate specific protective properties beyond basic requirements, allowing workers to select boots suited for particular environmental conditions.

FO - Fuel Oil Resistant

FO marking indicates the outsole is resistant to fuel and oil. The rubber compound will not deteriorate when exposed to petroleum-based substances, preventing degradation and maintaining slip resistance.

CI - Cold Insulation

CI marking means the boot provides insulation against cold. This protects feet in refrigerated environments, cold storage, outdoor winter work, and activities where cold exposure could cause discomfort or injury.

HI - Heat Insulation

HI marking indicates heat insulation from the outsole. Boots with HI rating protect feet from hot environments like foundries, welding, and high-temperature industrial settings.

TIPOur safety boots with FO, CI, and HI markings provide specialized protection for extreme work environments.

Related Tags

safety standardscertification requirementsCE markingASTM standardsEN ISO 20345

Frequently Asked Questions

Q:Can safety boots have multiple special markings?

Yes, safety boots can combine multiple markings like S3 + FO + CI + HI for comprehensive protection. However, not all combinations are available in every boot model. For more detailed information or specific requirements, please contact our team of safety footwear experts.

Q:What is the difference between CI and HI?

CI (Cold Insulation) protects feet from cold environments, while HI (Heat Insulation) protects feet from hot environments. They use different materials and construction techniques for opposing temperature extremes. When choosing between options, consider your specific workplace hazards, required protection levels, and comfort preferences. Different industries and work environments have varying safety requirements that should guide your decision. For example, electrical workers may prioritize EH protection, while construction workers need robust toe and puncture protection.

Q:Do I need FO rating if I work indoors?

FO rating is needed if exposed to oils, petroleum products, or greases regardless of indoor/outdoor setting. Automotive work, manufacturing, and machining often involve oil exposure even indoors. For more detailed information or specific requirements, please contact our team of safety footwear experts.