Under ANSI/ISEA Z89.1, hard hats are classified by the area of the head they protect:

• Type I — provides protection only at the top of the head (the crown). This is the most common type in general industry. All cap-style and most vented hard hats are Type I.
• Type II — provides protection at the top and sides of the head, reducing the risk from lateral impacts. Required in some construction environments and increasingly specified by safety-forward employers. Full-brim styles with thickened side walls are typically Type II.

Most hard hats in this category are Type I. If your hazard assessment identifies significant lateral impact risk (work near suspended loads, narrow spaces, or work at heights with overhead obstructions), consult ANSI Z89.1 and consider a Type II helmet.

ANSI Z89.1 classifies hard hats by electrical performance:

• Class E (Electrical) — tested to withstand 20,000 volts phase-to-ground. Required for electrical workers exposed to high-voltage conductors. The Securis SEC23-E and SEC24-E Electrical Grade helmets are Class E. The Pyramex Ridgeline is available in Class E (non-vented versions only — vented hard hats cannot be Class E).
• Class G (General) — tested to withstand 2,200 volts. Suitable for general construction and industrial work with incidental exposure to low-voltage electrical hazards.
• Class C (Conductive) — provides no electrical protection. Used where electrical hazard is not a concern and weight/ventilation is the priority. The Securis SEC23-C Construction Grade helmets are Class C.

Vented hard hats (including vented Pyramex Ridgeline models) are always Class C — the vents break the electrical insulation of the shell. If you work in environments with any voltage exposure, a non-vented Class E or Class G hard hat is required.

Mips (Multi-directional Impact Protection System) is a patented inner shell technology developed from brain injury research. Traditional hard hats are tested primarily for direct vertical impact (a weight dropped straight down onto the crown). However, most real-world head impacts involve an angled force that creates rotational motion — the brain's most injury-prone response, associated with concussion and diffuse axonal injury.

The Mips system adds a low-friction layer inside the helmet that allows the outer shell to rotate slightly (10–15mm) relative to the head upon angled impact, redirecting and absorbing rotational energy before it reaches the brain. The Securis SEC23-C, SEC23-E, SEC25-C, and SEC24-E all incorporate Mips and still meet ANSI Z89.1 requirements.

OSHA does not specify a mandatory replacement interval for hard hats, but ANSI Z89.1 and manufacturers provide guidance:

• Immediately after any impact — a hard hat that has absorbed a significant impact must be replaced, even if no visible damage is present. The shell may have micro-cracks that compromise future protection.
• Shell: every 2–5 years from first use — UV exposure, heat, and chemical contact degrade ABS and HDPE shells over time, reducing impact resistance. ANSI Z89.1 recommends manufacturers publish shell service life guidance. Most Pyramex and Securis helmets have a 5-year shell service life from date of first use.
• Suspension: every 12 months — the internal suspension degrades faster than the shell from sweat, oils, and flexing. Replace annually regardless of appearance, or whenever elastic or webbing shows wear.

Check the manufacture date stamped inside the shell (month/year or quarter/year) to track service life. Hard hats with visible cracks, dents, penetration marks, or chalky/faded shells from UV exposure should be replaced immediately.

Not universally — accessories must be specifically approved for use with the hard hat model by the helmet manufacturer. Adding unauthorized slots, holes, or attachments can compromise the structural integrity of the shell and void the ANSI Z89.1 rating.

Hard hat accessories should be selected from the manufacturer's approved list for that shell. For example, slot-mounted earmuffs and face shield brackets are approved for specific Pyramex Ridgeline models and must be specified by model number. The Portwest PS53 Height Endurance Helmet is designed to accept headtorch mounts and is compatible with specific Portwest face shield headgear. Check the Accessories subcategory for approved add-ons. Call 1-800-723-3620 for compatibility guidance.