You're right, the NEC doesn't have a specific volume threshold that triggers GFCI requirements. GFCI protection requirements are driven by the location (wet, damp, construction site) and/or the specific equipment used. There's no hard-and-fast rule based purely on the amount of liquid being handled.What you're likely remembering is recommendations or best practices from other sources, such as: Laboratory Safety Guidelines

Laboratory safety manuals, from organizations like the CDC or university safety departments, often recommend GFCI protection in areas where significant quantities of liquids are handled, even if the area isn't technically classified as "wet" or "damp." This is due to the increased risk of spills and contact with electrical equipment. These manuals often reference standards like ANSI/ISEA Z358.1 (for emergency eyewash and shower equipment), which may indirectly influence GFCI decisions near those fixtures.

NFPA 45 (Fire Protection for Laboratories Using Chemicals)

While NFPA 45 doesn't explicitly mandate GFCI protection based on liquid volume, it emphasizes hazard assessment and risk mitigation. Handling large volumes of liquids in a lab significantly increases the risk of spills and subsequent electrical hazards. This could lead a safety professional to recommend GFCI protection as part of a comprehensive safety plan.

UL White Papers or Technical Documents

UL sometimes publishes white papers or technical documents that provide guidance on interpreting their standards and applying them to specific situations. It's possible there's something like that out there that addresses liquid handling, but it would be advisory, not mandatory.

Why the Memory of 1.8 Liters Might Be Stuck

The 1.8-liter figure might be a red herring. Here's why:

Units Conversion

Is 1.8 Liters a conversion point for another volume measure? (Half a gallon = ~ 1.9 Liters - but that doesn't fit into a standards context.)

Accidental Spill Volume

1.8 Liters could be an estimate of the "realistic" volume of a single point of failure. If a container of 1.8 Liters fails it could realistically expose someone who is in the area.

What You Can Do (since there isn't a specific code to point to)


Perform a Hazard Assessment

This is the most important step. Analyze the specific tasks being performed, the types and volumes of liquids being used, the equipment involved, and the potential for spills or contact with electrical sources. Document the assessment.2.

Consult Industry Best Practices

Look at laboratory safety guidelines from reputable organizations (CDC, university safety departments, professional lab associations). See what they recommend for handling similar quantities of liquids.3.

Err on the Side of Caution

If there's any doubt, recommend GFCI protection. It's a relatively inexpensive safety measure that can significantly reduce the risk of electrical shock.4.

Document Your Rationale: If you choose not* to install GFCI protection in a situation where liquids are present, document your reasoning based on the hazard assessment.In summary, you're unlikely to find a specific NEC or UL requirement based solely on liquid volume. The decision on whether to use GFCI protection in a laboratory or similar setting should be based on a comprehensive hazard assessment, consideration of industry best practices, and a general commitment to safety. Flag for review