With the advancement of industrial and infrastructure projects, the selection of cables for fire safety is more than just a matter of flame resistance. Halogen-free cables or Low Smoke Zero Halogen (LSZH), are a critical specification because they significantly reduce smoke density and remove corrosive halogen gases in the event of fire. This has a direct impact on the evacuation visibility, protection of sensitive equipment and on the compliance with strict safety codes in the facilities. Here at Hulk Electric we have been assisting engineers with trusted halogen free cable solutions for these very requirements in the fields of automation, robotics and heavy industry.
Why Fire Safety Has Shifted Cable Selection Toward Halogen-Free and LSZH
The emphasis of modern approaches to fire safety is not only on preventing fire ignition, but also on reducing secondary fire effects such as heavy smoke, which prevents the escape route, and toxic and corrosive gases, which damage electronics and adversely affect people. Unlike traditional PVC cables, these cables do not emit considerable amounts of halogen acids, such as hydrogen chloride, during a fire, and the smoke is not so corrosive. By contrast, cables made with the special polymers generate little smoke and no halogen gases and are preferred in areas where there is a high concentration of people or when an enclosed area is involved.
This change is reflected in project specifications across a broad spectrum of plants, transport hubs and public buildings where downtime, liability and human safety are critical.
Fire-Behaviour Basics – FR-LS vs LSZH vs Fire-Resistant
Knowing the differences enables the specifier to select the appropriate cable, depending on the risk profile.
Flame-Retardant Low-Smoke (FR-LS / FRLS)
FR-LS cables have a lower rate of fire spread and smoke than PVC, but they still contain halogens. They give off toxic and corrosive gases when exposed to fire and therefore are suitable for areas where emergency evacuation and protection of equipment are not critical, but not recommended for areas that are more hazardous.
Low Smoke Zero Halogen (LSZH / LS0H / LSOH)
LSZH cables produce very little smoke and no corrosive gases at all, thus enhancing visibility during a fire and protecting against corrosive damage. They perform well in conditions of occupancy, enclosure and high value assets. Smoke density and acid gas emissions are among the key standards – IEC 61034 and IEC 60754, respectively.
Fire-Resistant Cables with Halogen-Free Jackets
These provide circuit integrity for emergency systems (such as fire alarms, lighting) in the event of a fire and are sometimes used together with LSZH outer jackets. Some projects are so critical they need fire resistant and halogen free performance in order to offer complete protection.
How LSZH Requirements Show Up in Modern Infrastructure Projects
In areas of high risk, project documents have been increasingly referring to LSZH directly.
High-Occupancy Buildings and Public Spaces
Hospitals, schools, shopping malls and high-rises call for LSZH for risers, escape routes and occupied areas. The most serious danger is dense smoke and toxic gases and codes frequently require low smoke/hybrid materials to support safe evacuation.
Airports, Metro Systems, and Transport Hubs
LSZH armoured cables are often used in airports, railway tunnels and metro lines in areas where passengers walk and where it is important that the cables function. Smoke and gas control is a must, especially since there is limited ventilation and complex evacuation paths.
Tunnels, Underground Installations, and Enclosed Corridors
Road and rail tunnels are ideal for the use of LSZH because of the lack of ventilation and extended escape routes. These cables minimise any secondary damage to structures and equipment and provide visibility for emergency responders.
Fire Safety in Plant Design – Where Halogen-Free Requirements Appear
This is the same for industrial plants, particularly in modern automated factories.
Production Plants, Laboratories, and Enclosed Industrial Spaces
Halogen-free cable solutions are needed to ensure the safety of people and electronics in control rooms, corridors, and staff spaces inside factories. In addition to the food & beverage or pharmaceutical plants, hygiene and audit requirements are suitable and complimentary to our high temperature and halogen-free lines.
Data Centers, Control Rooms, and Equipment-Dense Areas
Typical here are the LSHZ cables to protect the servers and instrumentation from corrosive smoke. In non-public industrial environments, the specification is justified by the faster post-incident recovery and less damage to assets.
How LSZH and Halogen-Free Requirements Are Expressed in Specs
Engineers need to be aware of the following phrases:
- ““Cables in occupied and enclosed areas shall be low smoke zero halogen (LSZH).”
- Fire resistant cables for emergency systems that have a “halogen-free outer sheath.
- PVC will not be accepted in tunnels or evacuation routes. LSZH to be used.
Commonly cited specifications include IEC 60332 (flame spread), IEC 61034 (smoke) and IEC 60754 (halogen acid).
Practical Fire-Safety Selection Guidance for Engineers
When LSZH Is the Default, and When FR-LS May Suffice
Use LSZH in closed/occupied areas, tunnels, metros, airports, data centers, control rooms. FR-LS can operate in open, ventilated, less hazardous areas; however, please check with local codes and client requirements before.
Key Fire-Safety Questions to Ask at Design Stage
- How are the buildings filled and how is the evacuation proceeding?
- What amount of critical electronics or high value equipment is in jeopardy?
- What are the specific requirements of the project and local laws?
These decisions early on in the documentation process lead to less rework during procurement.
Our halogen-free cables are designed for challenging automation applications that comply with important international fire-safety standards, such as high-flex, servo, robot and industrial Ethernet cables. Delivering compliant and reliable systems, we support our OEM and integrator customers with full traceability, custom options and proven performance in global projects.
Give us the details of your project and we’ll suggest the suitable halogen-free or LSZH solutions for your project fire-safety and operational requirements.
