Isocyanate Detectors Keep Workers Safe During Foam Manufacturing Process

Dec 13, 2020

Isocyanate Detectors Keep Workers Safe During Foam Manufacturing Process

by | Dec 13, 2020


a1-cbiss installed isocyanate monitors at a foam production facility in accordance with the site’s Environment Agency (EA) permit which requires monitoring of isocyanate levels.



A large manufacturing operation in the UK concentrates on supplying high quality engineered components to the international fenestration industry. Foam technologies weave, form and manufacture a wide variety of components. These include sealing solutions to aluminium, PVCu and timber applications and hardware systems in aluminium doors and windows.

The complex foam moulding process requires the control of interrelated variables. Heat, pressure, additives, resins, and density are part of the foam extrusions process. Each variable must be controlled in order to create a high-quality foam product.




As part of the production of foams, the manufacturing operation uses large quantities of Isocyanates that are held as liquids in large, stainless steel tanks. One of the most common forms of isocyanates is toluene diisocyanate (TDI). TDI is a liquid at room temperature and can cause asthma-like conditions when inhaled as an aerosol.

Prolonged exposure to concentrations of TDI can rapidly affect lung function. Short-term exposure to TDI can cause coughing, tightness of the chest, as well as skin irritation and eye irritation. Following the appointment of a new plant manager at the manufacturing operation, the company looked to modernise and update their safety systems.

The site’s Environment Agency (EA) permit requires monitoring of the isocyanate levels, but not continuously.

The plant manager decided that as part of the upgrade they wanted to have continuous monitoring to help keep their employees as safe as possible which was above and beyond what the EA required.

Isocyanate Monitoring SOLUTION

An a1-cbiss gas detection engineer carried out a complete site survey to evaluate a number of parameters including; the location of a potential leak, the potential rate of gas leak, the direction it would leak in, alarm thresholds and communication outputs.

Given the number of risks that the production and storage areas presented to workers, the site survey concluded that continuous area monitoring was required to protect workers. Isocyanate monitoring equipment is needed to log levels of gases and activate an alarm once the alarm threshold is met. In some cases, machines can be switched off to restrict gas production.

The alarms would need to be seen by all workers so they could begin the evacuation procedure. The management team also required access to data logs for reporting purposes.

Colorimetric technology is the only recognised technology used to measure isocyanates. Upon detection of the target gas, a chemical reaction between the gas and cassette-like paper tape creates a chemically impregnated colour stain, which in turn is analysed by a sophisticated optical system, converting the colour stain into a ppb measurement.

a1-cbiss recommended the DOD ChemLogic Continuous Gas Monitor (CL1) because it was highly appropriate for this application.

Following the initial site survey, a1-cbiss introduced DOD Technologies (manufacturer of the CL1) to the client to help advise with the complexities involved in the project and to provide further recommendations to simplify the project.

“The plant manager began to look into a fixed gas detection system that could provide employee confidence by providing an alarm should TDI exposure reach exposure limits. It was at this point that a1-cbiss were referred to the company because of their experience in designing colorimetric gas detection systems”


a1-cbiss, experienced in system integration sent an installation team to site to install the CL1 isocyanate monitors in accordance with the sites safety needs. a1-cbiss suggested that the site install several monitors at various points within the facility;

  • 8 production lines,
  • 4 exhaust stacks, and,
  • in the TDI tank room.

The client purchased CDAS Net which is an advanced data acquisition and reporting software designed by a1-cbiss. CDAS is connected to both the CL1 monitors and the central computer via Ethernet to control the alarms and produce data fed reports.

A Flexible System

The ease and flexibility of CDAS allow user-defined profiles to be created allowing several of these profiles to exist at once. a1-cbiss have created a profile for the clients’ management team giving them access to all the historical data and run reports.

The secondary profile is displayed using CDAS on a large 55” screen on the shop floor. The screen can be seen by all workers giving them the confidence that they are working in a safe environment. It also allows maintenance issues to be noticed and dealt with quicker.


Key Points

  • Alarm levels are planned in line with current EH40 guidelines for measuring TDI.
  • The CL1 isocyanate monitors are set to two independent alarm thresholds, which trigger a relay alarm once thresholds are reached.
  • The alarm is connected to a local beacon & sounder for local notification to alert production staff to evacuate the area.
  • The client also purchased the CLPX to allow for spot-checking areas that aren’t covered with a fixed CL1 monitor.
  • The CLPX also provides a back-up to the CL1 to double-check readings in the event of an alarm.
  • As with any fixed isocyanate monitors, the paper-tape cassettes need to be changed every 30 days.
  • The CL1 employs paper-saving technology which ensures that the tape is only used once it detects just a small amount of gas.

To find out more about how you can help keep workers safe from isocyanates, contact a1-cbiss