During Fire, the actual danger in a cable fire in confined areas such as tunnels, control rooms, data centers and underground facilities is not the flames but the dense, toxic smoke and corrosive gases generated by non-halogen-free cables. In many installations, standard PVC-jacketed cables emit dense and acidic smoke which can quickly lower visibility, endanger personnel and harm sensitive electronics.
With more than 15 years of experience producing high performance cables that resist the effects of fire in harsh industrial environments, Hulk Electric has first-hand knowledge of the significant decrease in these risks that can occur by selecting the right materials. This guide explores the grave consequences of using non-halogen-free cables in enclosed environments and why it makes sense to invest in low-smoke zero-halogen (LSZH) solutions for safety and reliability.
Why Confined Spaces Are High-Risk for Cable Fires
Limited ventilation allows gases and smoke to build up rapidly, making confined spaces a greater fire danger. Smoke by-products from combustion are trapped in tunnels, cable basements and control rooms which result in virtually no visibility and unsafe breathing conditions within minutes.
These “dense cable” environments, which are typical in data centers, transport systems, and industrial automation, have a higher density of cables, which equals more fuel for a fire. A small fire can quickly get out of control and cause confusion during evacuation and wreak havoc on the emergency systems.
Smoke Behaviour of Non-Halogen-Free Cables in Confined Spaces
Dense Smoke and Visibility Loss
Non-halogenated cables, especially PVC sheathed cables, produce dense black smoke in large quantities in the event of fire. This smoke can cause the visibility to become extremely low, making it difficult to see exits, signs or rescue routes, particularly in tunnels or underground facilities.
Toxic Gases and Health Risks
When burning materials contain the element of halogen, they produce hydrogen chloride and other corrosive gases. These also combine with the moisture to create acid which irritates and harms respiratory systems, making them vulnerable to long-term health problems and suffocation for people who might be affected.
Corrosion and Damage to Electronics and Infrastructure
How Smoke Damages Electronics
When burning PVC cables, acidic smoke residues can damage circuit boards, connectors and metal contacts. This can result in short circuits, malfunctions and permanent damage to control systems, servers and automation equipment – frequently, this is more expensive than the fire.
Corrosive Gases and Structural Damage
Hydrogen chloride gases cause continuous corrosion of metals and building materials. The residues can lead to secondary damage that often outweigh the primary fire damage, and which can be further destructive of equipment long after the fire is out if not neutralized in time.
Cleanup Complexity and Hidden Corrosion
Professional decontamination is necessary because it requires specialized cleaning that will remove the particles that are acidic. If not completely cleaned up, incomplete cleanup results in latent failures, longer outages, and reliability issues.
Downtime and Recovery Costs After Smoke and Corrosion Events
Smoke and corrosion frequently result in extended shutdowns for inspection, cleaning and replacement. The hourly down time price tag for data centres or critical infrastructure can be tens or hundreds of thousands of dollars. Recovery is time-consuming, as it includes dehumidification, component replacement, and whole system testing.
How Halogen-Free Cables Change the Fire Scenario
Low Smoke, Better Visibility
More importantly, LSZH cables generate much less smoke, meaning that there is a greater visibility for easy evacuation and quick emergency response.
No Toxic Halogen Gases, Less Corrosion
These cables produce little corrosive gases without the involvement of the halogens, which helps prevent damage to electronics and decrease clean up after a fire.
More Controlled Fire Behaviour
Advanced formulations with mineral fillers ensure excellent flame retardancy, a lower flame spread, self-extinguishing properties and standards such as IEC 60332, IEC 60754, IEC 61034.
Practical Guidelines for Cable Selection in Confined Spaces
- Determine high risk areas: Tunnels, data centers, control rooms, underground buildings, and enclosed industrial corridors.
- Evaluate occupancy and equipment sensitivity — Prioritize areas where people are or where critical electronics are.
- Indicate materials for LSZH – Do not use cables where smoke or corrosion would be a significant problem.
- Do not accept IEC products without documented performance, as specified in IEC 60754 (halogen content), IEC 61034 (smoke density) and IEC 60332 test reports.
- Installations, plan with care — Use cables installed in confined/high-risk areas that are halogen free, and standard cables in well-ventilated, low-risk areas.
The material of a cable can have an effect on safety, equipment safety and continuity of operations in confined areas. Although non-halogen-free cables can be less expensive initially, smoke, corrosion and downtime can become a significant expense.
Hulk Electric also offers bespoke halogen-free cables, such as those responsible for low smoking in industrial automation, robotics and critical equipment applications. We comply with the most demanding international certifications and are designed to be reliable in the most challenging environments. Talk to our team to understand your project needs and how our halogen free cables can protect your facility.
