01Safety

Signal words

This handbook and the manual use the same signal words. They differ in severity, so read them as such.

What this stack is for

HXS-2 is for producing hydrogen and oxygen from an alkaline electrolyte, and nothing else. Operate it within the limits in this handbook and the datasheet.

Do not

• Run it on a different electrolyte
• Run it outside the current, voltage, pressure or temperature limits
• Modify its structure, or dismantle or repair it without authorisation

Use of this kind can injure people and damage property or the environment.

Who should work on it

This document is for integrators designing a BoP around the stack, researchers running it in a lab or pilot facility, and trained operators running it inside a system. You should be familiar with four things.

• Hydrogen safety, and hydrogen and oxygen venting, ventilation and vent routing
• High-current DC power equipment and electrical hazards
• Alkaline electrolyte handling and chemical safety procedures
• The fundamentals of water electrolysis systems

Hydrogen

• Operate only in a well-ventilated area, or connect the vents to an engineered exhaust system.
• Do not operate in a sealed room or a small unventilated enclosure.
• Keep ignition sources away: no smoking, open flames, welding, grinding or spark-producing work near the stack or the vent outlets.
• Use electrical equipment suitable for the area classification where hydrogen may be present.
• Check for leaks by an approved method, such as an approved hydrogen detector. Never use an open flame to find a leak.
• Hydrogen collects at ceilings and other high points. Take that into account when planning ventilation.

Vent lines

• Vent lines must stay open. Fit no valve or device that could inadvertently close one.
• Do not restrict a vent line or create backpressure.
• Keep vent and relief lines free of obstructions, kinks, debris and unintended liquid accumulation.
• Accumulated condensate can freeze a vent shut. Use slope, drain points, insulation or heat tracing as your site conditions require.
• Route the vent outlets away from ignition sources and follow local codes and site safety rules.
• An oxygen-enriched atmosphere raises the fire risk. Keep combustibles away from the oxygen discharge area and ensure ventilation around the outlets.

Electrical

• All electrical installation is done by qualified personnel.
• Provide overcurrent protection and a disconnecting device to your local code.
• Earth the DC supply and all connected equipment properly.
• Never connect or disconnect power cables under load.
• Confirm the polarity and make the terminations secure. A loose connection leads to overheating and arc faults.
• Keep electrical components dry and protected from contact with electrolyte.

Electrolyte

• Handle it according to the SDS and your site procedures.
• Use only KOH-compatible materials, for containers, tubing and fittings alike.
• For a spill, contain it, clean it up by your site procedure, and dispose of the waste to regulation.
• On exposure, flush with water immediately and seek medical attention as required.
• Keep an eyewash station and a safety shower near where KOH is handled.

PPE

Emergency shutdown and response

A gas or electrolyte leak, an unusual noise, smoke, a nearby fire, or visible damage

1. If it is safe to approach, stop the DC output to the stack and leave it off.
2. Warn the people nearby, evacuate non-essential personnel and restrict access.
3. Do not touch terminals, cables or wetted lines until the area is safe and the equipment secured.
4. Follow your site emergency response plan and notify the responsible safety officer.
5. Do not resume operation until qualified personnel have identified and corrected the cause.

A hydrogen leak, or a suspected one

A vent suspected of being blocked or iced

A spill or chemical exposure