At around 4:00 a.m., a fire broke out on the dispenser heads of a production line of a factory that manufactures polyurethane foam (PUF) panels. At 3:55 a.m., the formulation and facing were changed. At 4 a.m., flames appeared between the conformer and the conveyor when adhesive-tape gluing for the new facing started. The technicians battled the flames with fire extinguishers and a fire hose. The sprinkler system activated at 4:08 am, automatically alerting the factory’s alarm monitoring company, which contacted the site’s maintenance department. The shift leader called the firefighters at 4:15 a.m. They arrived at 4:35 a.m., at the same time as the on-call manager and the maintenance manager, and evacuated the 14 employees present. The sprinkler heads operated for two hours.

A total of 17 m³ of water was sprayed. The production line was shut down for 10 days. A total of 20 m³ of solid waste was disposed of in a landfill and the 15 m³ of liquid waste was sent to technical treatment centres. The polyurethane had reacted with 2 m³ of water. The mechanical and electrical components were dismantled, checked, and replaced as necessary.

The accident was caused by PU foam that had accumulated at the conveyor inlet after the facing burst. Electrostatic energy at the facing/Mylar® traction tape then caused the foam to ignite. The incident was exacerbated by two factors: the emergency stop of the dispenser heads was not activated and the high flow rate used to manufacture the thick plates (160 mm) fed the flames.

As an immediate measure, the operator told its employees that the dispenser heads’ emergency stop must be activated when an abnormal amount of foam builds up at the inlet, as this indicates that the facing has burst.

In the medium term, the operator is taking the following measures:

• checking whether the emergency stops located outside the dispenser head booth, on the facing reels, are activated when the dispenser heads shut off. If not, looking into the feasibility. If infeasible, it will install an emergency stop outside the booth and do the same for the other similar lines;
• looking into the possibility of installing breakage detectors on the facing reels and having the alarm relayed near the line-head room;
• looking into the feasibility of installing a detector (light beam) at the inlet of the conformer and conveyor belt to check the foam level. If it is too high (i.e., breaks the light beam), it will provide a control to shut off the dispenser heads;
• considering training more employees in turning off the sprinkler system so that it does not spray excess water and cause additional damage.