Asphyxiating Atmosphere Sign

Asphyxiating Atmosphere Sign – ISO 7010 Warning Symbol HS0029

This Asphyxiating Atmosphere sign warns crew and contractors that a compartment may contain air with insufficient oxygen to sustain consciousness, whether from displacement by inert gas, cargo off-gassing or poor ventilation. It follows the internationally recognised ISO 7010 warning pictogram format, showing a collapsed figure inside a cloud of particles on the standard photoluminescent yellow triangle so the asphyxiating atmosphere hazard reads instantly regardless of the reader’s first language.

As SKU HS0029 in the Hazard Signs range, it is built for continuous marine exposure and suits ballast tanks, cargo holds, void spaces, inert gas system compartments and any enclosed space subject to confined space entry procedures.

The pictogram shows a figure slumped on the ground surrounded by a scattered dot pattern representing displaced or contaminated air, rendered in black inside the warning triangle, a graphic that communicates the collapse risk of an asphyxiating atmosphere without needing a gas reading or text explanation.

Because an oxygen-deficient atmosphere gives no sensory warning before consciousness is lost, the sign functions as one of the only pre-entry cues available, reinforcing the requirement to test the atmosphere and follow permit-to-work procedures before anyone enters a marked space. The photoluminescent base keeps the asphyxiating atmosphere warning visible for a period after lighting fails, relevant for tank and void space entrances accessed during rounds.

Why Asphyxiating Atmosphere Marking Matters

Entry into an asphyxiating atmosphere without testing and ventilation remains one of the leading causes of multiple fatalities aboard vessels, often because a would-be rescuer follows a collapsed colleague into the same untested space.

Standardised signage at every confined space entrance reinforces the ship’s enclosed space entry procedure, reminding crew to test the atmosphere, ventilate, and use a permit before entry rather than relying on visual inspection alone. It also gives visiting surveyors, contractors and new crew an unmistakable warning at spaces they may not recognise as high-risk from appearance alone.

Compliance and Certification

This sign is produced to align with IMO shipboard safety signage guidance and the ISO 7010 graphical symbol set used to flag confined space and atmospheric hazards, supporting the SOLAS and ISM Code requirements for enclosed space entry procedures and drills aboard vessels. A visible asphyxiating atmosphere warning at tank and void space entrances is a documented control that flag-state inspectors, classification surveyors and Port State Control officers specifically check for during enclosed space compliance reviews.

Installation Recommendations

Mount the sign directly at every access point to a compartment subject to confined space entry procedures, including tank lids, void space manholes and cargo hold access ladders, at a height that is seen before the access point is opened. Use the pre-drilled fixing holes with marine-grade fasteners for exterior deck fittings, and the self-adhesive backing for interior hatch covers and manhole surrounds. Confirm during enclosed space drills and audits that every relevant entry point carries the asphyxiating atmosphere warning and that it remains legible.

• 425 x 425mm rigid or self-adhesive format for steel, aluminium or GRP surfaces
• Photoluminescent base for visibility during power loss or blackout drills
• UV-stable, saltwater-resistant construction for long-term exterior exposure
• Self-adhesive or pre-drilled fixing options for fast, secure installation
• ISO 7010 compliant collapsed-figure pictogram, language-independent and instantly recognisable

Order the HS0029 Asphyxiating Atmosphere sign today to mark every confined space entrance before your next enclosed space drill or audit. Safety Sign Hub stocks the complete IMPA/ISSA-coded hazard sign range and ships marine-grade signage across Australia and to vessels in port, with bulk pricing for fleet orders.

See the full Hazard Signs range for related ISO 7010 warning pictograms, or browse our Fire Fighting Signs for IMO A.654(16) fire control signage to complete your vessel’s safety signage plan.