5.3 Eyewash, PPE, Materials Compatibility, and ASME B31.5 Piping

Eyewash and Shower — The SDS 15-Minute Flush Has to Be Physically Possible

Quick Answer: ANSI Z358.1 is the emergency eyewash and shower standard. The injured person must be able to reach the unit in about 10 seconds (commonly taught as ~55 ft), on the same level, with no locked doors, pallets, or stairs in the path, and flush both eyes and body for 15 minutes with tepid water, typically 60–100°F. IIAR 2 machinery-room design expects this capability in the engine room. Squeeze bottles in a desk do not replace a plumbed unit.

Ammonia in the eyes is a race. Alkali keeps saponifying tissue after the splash. The SDS said 15 minutes of water. ANSI Z358.1 is how the plant makes that instruction real:

• Duration. The unit must deliver water long enough for a 15-minute flush without the injured person having to move to a second hose. A 30-second burst that then dies is a failed unit.
• Tepid water, typically 60–100°F. Ice-cold well water makes people abandon the flush at two minutes. Scalding water adds burns. Tepid is how you get 15 minutes of actual flushing.
• Ten-second travel, about 55 feet. The standard's requirement is reach in 10 seconds, unobstructed. Industry training converts that to about 55 ft of clear path. Measure walking time with the obstacles that are actually there on a Monday, not the empty aisle on the drawing. Same floor — do not send a blinded operator down a stair tower.
• Use both hands on the eyes, so the valve stays open. Hands-free stay-open eyewash and a shower pull-rod the person can find by feel. Teach the location on every engine-room tour.
• Activation and inspection. Z358.1 programs activate plumbed units on a weekly cadence to clear scale and prove flow, and inspect more thoroughly on the manufacturer's interval. A CIRO who cannot remember the last activation has an integrity problem, not a paperwork preference.
• Personal wash bottles are a bridge to the plumbed unit, not a substitute. They do not deliver 15 minutes.

IIAR 2 machinery rooms are wet, chemical, and full of liquid ammonia flanges. Emergency eyewash and safety shower capability belongs in that occupancy, not three rooms away behind a card reader. If a pallet of oil drums is stored in the 10-second path, you failed both Z358.1 and the IIAR 2 combustible-storage idea from the design chapter.

After the hardware works, the first-aid rules do not change: flush 15+ minutes, remove clothing and leather while flushing, fresh air for inhalation, medical care, no acid neutralization.

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PPE — Eyes, Lungs, Skin, and When SCBA Is the Only Honest Answer

Match clothing to the task and the atmosphere, not to the logo on the jacket.

Chemical goggles and a face shield address liquid. Ammonia vapor also attacks the eyes; a full-face respirator or goggles under a hood is not vanity. Chemical gloves mean a glove the SDS and the plant PPE matrix actually list for ammonia (commonly butyl or similar chemical-resistant types in plant programs) — not the leather glove that will soak and hold NH3 against the skin. Splash protection means the liquid cannot run into boots and waistbands.

Respirators are not generic. Ammonia needs an ammonia-rated cartridge or, in IDLH/unknown conditions, atmosphere-supplying protection. SCBA for IDLH or unknown is the sentence the exam wants. A 170 ppm engine room with no portable reading at the valve you intend to crack is an unknown that can become IDLH when the flange opens. That is not a cartridge job.

Cartridge limits still apply when the atmosphere is known and below IDLH: oxygen must be adequate, the cartridge has a service life, breakthrough is real, and facial hair breaks the seal. None of those caveats turn a cartridge into SCBA.

PPE does not replace isolation. The best glove is the king valve you closed from a safe location so the flange you open is pumped down.

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Materials Compatibility — Ammonia Attacks the HVAC Metals You Grew Up With

Halocarbon service uses copper tubing. Ammonia does not. Moisture plus ammonia plus copper, brass, or bronze produces corrosion and stress-corrosion cracking. Zinc and galvanized coatings are attacked. Putting a brass gauge valve, a copper instrument line, or a galvanized fitting into an NH3 system is how you buy a leak and a contaminated charge.

Compatible families used in industrial ammonia plants:

• Carbon steel and iron. The default piping, vessels, and many valve bodies.
• Stainless steel. Common for stems, trim, some tubing, and corrosive locations.
• Aluminum, with caveats. Aluminum is generally listed as compatible with dry anhydrous ammonia and appears in some equipment. Aqueous / wet ammonia can attack aluminum. Do not assume a copper-aluminum HVAC coil or an unmarked aluminum fitting is ammonia-rated. If the SDS or IIAR materials guidance says the service is wet, do not improvise aluminum.

Never in ammonia piping or components:

• Copper and copper alloys (brass, bronze)
• Galvanized steel
• Zinc (coatings, fittings, some instrument parts)

SDS Section 10 often lists those incompatibles next to acids, oxidizers, and certain metals in instruments. That list is PSI. A contractor who says refrigeration piping is always copper is installing the wrong code and the wrong metal.

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ASME B31.5 — Refrigeration Piping, Not a Copper Soft-Set

ASME B31.5, Refrigeration Piping and Heat Transfer Components, is the piping code CIRO candidates should name for industrial refrigeration piping. It is not a permission to use B31.1 power piping habits or halocarbon copper practice. It covers materials, design, fabrication, assembly, inspection, and testing of piping for refrigerants and secondary coolants. On an ammonia plant, B31.5 plus IIAR 2 materials rules means steel (or other compatible) pipe, designed joints, and documented testing — not Type L copper tubing.

Supervisor-level B31.5 / plant-piping practices the exam will recognize:

• Identification. Pipe markers that state the contents (NH3), physical state (liquid, suction vapor, hot gas), pressure level, and flow direction. A bare silver line that everyone on dayshift remembers is not identification on nights or for the fire department.
• Supports. Hangers and sleepers sized for pipe, insulation, ice, and dynamic loads. Do not hang a four-inch hot-gas line from a one-inch conduit or from another refrigerant line. Cold lines move and collect ice; supports must allow that without tearing insulation or lifting a valve off its flange.
• Expansion. Hot-gas, defrost, and discharge lines grow. Suction lines contract. Loops, offsets, anchors, and guides (and only expansion joints that are ammonia-compatible) keep thermal movement from fatiguing welds and breaking isolation valves. A rigidly locked long run is a crack waiting for the next defrost.
• Isolation valves. Every piece of equipment that must be pumped down needs isolation that matches the P&ID. Do not trap liquid ammonia in a no-relief pocket; hydraulic expansion will lift a gasket or a head. Isolated volumes need relief back to the system or to a relief device as designed.
• King valve. The king valve is the main liquid stop on the outlet of the high-pressure receiver (or the plant's designated main liquid supply stop). Closing it stops liquid feed to evaporators and recirculators. It is an emergency and maintenance isolation, not a throttle. Operators should be able to walk to it in the dark from the principal door path. It does not replace the refrigeration e-stop, and the e-stop does not replace knowing where the king valve is.
• Dual relief. Vessels require pressure-relief protection. Dual relief valves with a three-way dual-stop (selector) let you isolate one PRV for replacement while the other stays online, so the vessel is never left without relief. Do not leave a selector in a fantasy mid-position; proper dual-stops are built so one path remains open. Dual relief is mechanical integrity and B31.5/IIAR relief practice, not a spare part on a shelf.
• No copper tubing on ammonia. Instrument leads, oil lines, and contractor repairs all fail this test if someone grabs HVAC copper. Use compatible tube and fittings.

Walk an engine room with this checklist: markers readable, supports not using other pipes as beams, expansion loops not used as hangers for electrical cable, isolation valves accessible, king valve labeled and not seized, dual-relief selector clearly indicating which PRV is in service, and zero copper on the ammonia side.

A CIRO who can quote the PEL but still lets a brass isolation valve onto a liquid line has not finished the hazards chapter. The chemical, the SDS, the detectors, the eyewash, the respirator, and the pipe metal are one system.