ANSI/ISEA Z358.1

Q: What happens if the water is too cold or too hot?

Water below 60°F can cause hypothermia during a 15-minute drench shower. Water above 100°F can increase chemical absorption into skin and cause thermal burns. Both are violations of Z358.1, and both put the injured person at additional risk.

Emergency Eyewash and Shower Equipment

Last updated: April 2, 2026

Overview

ANSI/ISEA Z358.1 is the consensus standard for emergency eyewash stations and drench showers in the workplace. It defines the minimum performance requirements for equipment that flushes eyes, face, or body after contact with hazardous materials. The current edition is Z358.1-2014.

OSHA does not have its own detailed standard for eyewash and shower equipment. Instead, OSHA 1910.151(c) says "where the eyes or body of any person may be exposed to injurious corrosive materials, suitable facilities for quick drenching or flushing of the eyes and body shall be provided." The word "suitable" is where Z358.1 comes in. OSHA compliance officers use Z358.1 as the benchmark for what counts as suitable.

The standard divides equipment into two categories: mandatory and supplementary. Mandatory equipment (plumbed eyewash stations, combination units, drench showers) must meet all the flow rate, temperature, and duration requirements. Supplementary equipment (personal eyewash bottles, drench hoses) is meant for immediate first response only and cannot substitute for mandatory equipment.

Equipment Types

Z358.1 defines six categories of emergency equipment. Each has its own flow rate, flushing duration, and use case.

Equipment Type	Minimum Flow Rate	Flushing Duration	When to Use
Plumbed Eyewash	0.4 GPM	15 minutes	Primary protection anywhere corrosives are handled
Self-Contained Eyewash	0.4 GPM	15 minutes	Locations without plumbing access
Personal Eyewash	0.4 GPM (during use)	Seconds only	Supplemental. Immediate first response before reaching a station
Eye/Face Wash	3.0 GPM	15 minutes	Splash hazards that may contact both eyes and face
Drench Shower	20 GPM	15 minutes	Full body exposure to corrosives, acids, or caustics
Combination Unit	Eyewash + shower simultaneously	15 minutes	Areas with risk of both eye and body exposure

Personal eyewash bottles (the squeeze bottles you see in first aid kits) are supplementary only. They buy you time to walk to a plumbed station. They do not count as your primary eyewash equipment under Z358.1.

The 10-Second Rule

Z358.1 requires that emergency eyewash and shower equipment be reachable within 10 seconds of normal walking from the hazard. This is the single most cited requirement in the standard and the one that causes the most OSHA citations.

The 10-second walk is measured along the actual path someone would take, not a straight line. It accounts for doors, corners, and obstacles. A few things the standard spells out:

Equipment must be on the same level as the hazard. No stairs, no ladders.
The path must be free of obstructions. No locked doors, no equipment blocking the route.
The path must be well-lit and clearly marked with signage per ANSI Z535.
For strong acids or caustics, many safety professionals recommend placing equipment closer than 10 seconds because the first few seconds of flushing are the most critical for limiting tissue damage.

Common violation: Storing materials in front of an eyewash station or letting a door stay locked on the path to the shower. During an inspection, OSHA will walk the path themselves and time it. If a forklift or pallet is blocking access, that counts as an obstruction.

Water Requirements

Z358.1 specifies three water parameters: temperature, flow rate, and duration. Getting any of them wrong can turn a safety device into a hazard.

Tepid water temperature

The standard requires tepid water, defined as 60 to 100 degrees F (16 to 38 degrees C). Water below 60 degrees F causes hypothermia during a 15-minute flush, especially with drench showers where the whole body is wet. Water above 100 degrees F can increase the rate of chemical absorption into tissue and cause thermal burns on top of chemical burns.

In cold climates or unheated warehouses, this often means installing a mixing valve or thermostatic tempering valve. In hot climates, you may need insulated supply lines or a recirculating system to keep water below 100 degrees F.

Flow rate and duration

Equipment	Minimum Flow	Duration	Total Water Needed
Eyewash	0.4 GPM	15 min	6 gallons
Eye/Face Wash	3.0 GPM	15 min	45 gallons
Drench Shower	20 GPM	15 min	300 gallons
Combination (eyewash + shower)	Both simultaneously	15 min	306+ gallons

For combination units, the eyewash and shower must be able to run at the same time at full flow. If turning on the shower drops the eyewash below 0.4 GPM, the unit does not meet the standard.

Portable vs Plumbed

Plumbed units connected to a potable water supply are the gold standard under Z358.1. They deliver unlimited flow at the correct temperature. But not every location has plumbing, and that is where self-contained and portable units come in.

Self-contained eyewash stations

Self-contained units hold their own water supply and do not connect to plumbing. Z358.1 allows them as primary equipment if they can deliver 0.4 GPM for 15 minutes. The catch is maintenance. Stagnant water grows bacteria. You need to either replace the water on a schedule (typically every 90 to 180 days, per the manufacturer) or use a preservative additive.

Personal eyewash bottles

Personal eyewash bottles (like the 16 oz or 32 oz squeeze bottles in first aid kits) are supplementary equipment only. They provide immediate flushing for a few seconds while the injured person walks to a full station. Some jurisdictions allow them as primary equipment in very low-risk environments, but under Z358.1, they are never a substitute for a plumbed or self-contained station.

Check expiration dates. Sealed sterile cartridges typically last 24 months.
Replace immediately after any use, even partial use.
Keep at least two bottles accessible per work area when used as supplemental.

Water quality

Z358.1 requires that flushing fluid be "preserved" to prevent microbial growth. For plumbed units, weekly activation handles this by flushing stagnant water from the line. For self-contained units, you must either change the water on a set schedule or add a bacteriostatic preservative. Do not use tap water without a preservative in a self-contained unit. You will have a bacteria problem within weeks.

Installation Requirements

Z358.1 specifies mounting heights, clearances, and accessibility requirements. Getting these wrong is a common reason for failed inspections.

Requirement	Eyewash / Eye-Face Wash	Drench Shower
Nozzle / head height	33 to 53 inches above floor	82 to 96 inches above floor
Clearance from wall	Minimum 6 inches from wall or nearest obstruction	Minimum 16-inch diameter unobstructed area
Activation	Single motion, hands-free once activated	Single pull, stays on without hand pressure
ADA accessibility	Must be accessible to wheelchair users	Must be accessible to wheelchair users

Signage is required at every station. Use ANSI Z535-compliant signs that are visible from the normal work area. Green and white "Emergency Eye Wash" or "Emergency Shower" signs are standard. Glow-in-the-dark or illuminated signs are recommended for areas that could lose power.

Floor drainage is not required by Z358.1 itself, but it is strongly recommended. A drench shower running at 20 GPM for 15 minutes puts 300 gallons of water on the floor. Without a drain, you will have a slip hazard and potential water damage. Most building codes and facility managers require drainage under showers.

Weekly Testing and Maintenance

Z358.1 requires a specific testing and maintenance schedule. The most important task is the weekly activation test.

Frequency	Activity	Purpose
Weekly	Activate plumbed units and let water flow	Flush stagnant water, verify operation, prevent bacterial growth
Weekly	Visual inspection of self-contained units	Check fluid level, look for contamination or damage
Annually	Full inspection by qualified personnel	Verify flow rate, check temperature, inspect plumbing connections
Per manufacturer	Replace self-contained fluid or cartridges	Maintain sterility (typically 90 to 180 days)

Keep a written log of every weekly activation and annual inspection. Tag or sign the unit with the last test date. This is the first thing an OSHA inspector asks to see. If you cannot produce a log, the inspector will assume the equipment has not been maintained.

Warning: Skipping the weekly flush on plumbed eyewash stations is the most common maintenance failure. Stagnant water in the supply line grows Legionella and other bacteria. Flushing contaminated water into an injured person's eyes can cause a secondary infection that is worse than the original chemical exposure.

Industry Applications

Different industries face different chemical hazards and need different equipment configurations. Here is a breakdown of typical setups.

Industry	Typical Hazards	Recommended Equipment
Laboratories	Acids, bases, solvents, biological agents	Combination eyewash/shower at every exit, personal bottles at benches
Manufacturing	Cutting fluids, degreasers, battery acid	Plumbed eyewash per work cell, drench showers near chemical storage
Food Processing	Cleaning chemicals (caustic soda, sanitizers), ammonia refrigerant	Combination units near CIP stations, eyewash near ammonia compressors
Construction	Concrete (highly alkaline), adhesives, solvents, silica dust	Portable self-contained eyewash, personal bottles in first aid kits
Warehousing	Battery charging stations (sulfuric acid), cleaning chemicals	Plumbed eyewash near battery rooms, self-contained units in aisles

The specific equipment you need depends on your hazard assessment. Review SDS (Safety Data Sheets) for every chemical on site. If any SDS says "flush eyes with water for 15 minutes" or "drench affected area," that chemical triggers Z358.1 equipment requirements.

Frequently Asked Questions

Does OSHA require ANSI Z358.1 compliance?

OSHA does not directly mandate Z358.1. However, OSHA 1910.151(c) requires "suitable facilities" for eye and body flushing, and OSHA compliance officers use Z358.1 as the benchmark for what qualifies as suitable. In practice, if your equipment does not meet Z358.1, you will likely receive a citation.

Can personal eyewash bottles replace a plumbed eyewash station?

Under Z358.1, no. Personal eyewash bottles are classified as supplementary equipment. They provide immediate first response while the injured person reaches a full station. Some jurisdictions allow them as primary in very low-risk settings, but the standard itself does not.

How far is a 10-second walk?

There is no fixed distance because it depends on the path. A straight, unobstructed hallway might allow 55 feet in 10 seconds. A path with turns, doors, or obstacles will be shorter. The standard measures time, not distance, so you need to actually walk the route and time it.

What happens if the water is too cold or too hot?

Water below 60 degrees F can cause hypothermia during a 15-minute drench shower. Water above 100 degrees F can increase chemical absorption into skin and cause thermal burns. Both are violations of Z358.1, and both put the injured person at additional risk.

How often do eyewash stations need to be tested?

Plumbed units must be activated weekly to flush stagnant water and verify operation. Self-contained units need weekly visual inspection. All units get a full annual inspection with flow rate and temperature verification.

Is floor drainage required under emergency showers?

Z358.1 does not require floor drainage, but it is strongly recommended. A drench shower puts 300 gallons on the floor during a 15-minute flush. Most building codes and facility requirements call for drainage to prevent slip hazards and water damage.