Lenzing in Upper Austria is the home site of a fibre producer that makes viscose, modal and lyocell from wood pulp. This page is for the plant, HSE and instrumentation teams who ask what an explosion proof mobile phone can and cannot do in a cellulose fibre works in Austria, and it is candid about one point: the IS-04Z1, an intrinsically safe Zone 1 and Zone 21 phone still in certification, currently targets temperature class T4, which matters a great deal next to carbon disulfide.
Launching Q4 2026 · ATEX certification in progress
Lenzing is described in public sources as the largest integrated pulp and viscose fibre production site in the world, and it is also the company's head office. Wood is turned into pulp, the pulp is converted to fibre, and the energy and chemical recovery systems behind both run on the same grounds, along with hydropower on the river. In the classic viscose and modal routes, cellulose is treated with carbon disulfide to form a soluble xanthate and then spun into an acid bath, which releases carbon disulfide and hydrogen sulfide into the spinning and recovery areas. Lyocell uses a different, closed-loop solvent system. Cut staple fibre and pulp sheets add cellulose dust and lint. So one site carries a very low ignition temperature gas, toxic gas and fibrous dust.
A cellulose plant is wet, hot and chemical. The marking of the device and its temperature class decide where it is allowed, and these are the points to put on the table.
Because carbon disulfide ignites at a very low temperature, areas for it are normally specified at T6. The IS-04Z1's marking target is II 2 G Ex ib IIC T4, so as designed it is not a candidate for a carbon disulfide area. That is stated here so nobody finds out at a site audit.
The same site has large areas that are not classified for carbon disulfide: wood handling, pulp and fibre dust areas, utilities, yards and tank farms. A Zone 21 and Zone 1 device suits those, and the plant's classification drawings decide each one.
Spinning halls are humid and chemical. IP68 sealing protects the electronics, but the housing material and cleaning chemicals have to be checked against the process, so request that data before any trial and do not assume it.
Lenzing is a works with several production lines and long distances between them. Four-constellation GNSS and a battery specified for a shift suit foot or bicycle rounds, and the console can restrict applications by area.
Cellulose dust and lint settle on cable trays and ledges, and cleaning rounds are how the plant controls them. A handset that records the round with photographs and positions gives the HSE team evidence for the explosion protection document.
A spinning line is stopped, purged and handed over to contractors for repairs. Isolation photographs, permits and sign-offs recorded on a managed device stay with the work order.
Utility staff check boilers, turbines and electrical rooms across the site. A handset that carries the checklist and a call function replaces the radio for non-process areas.
We have not found a public supplier registration route at Lenzing and claim none. What the safety and engineering teams will ask is clear from the chemistry. The first question will be the temperature class on the certificate, and an honest answer decides at once which areas the device can enter. Procurement and HSE teams should say which supplier induction and which approval steps apply to equipment brought onto the site.
As designed, no. The target marking is T4, while carbon disulfide areas are normally T6. Certification is still in progress and the final certificate sets the scope, so Lenzing's engineers should rely on that and not on a design target.
Areas not classified for carbon disulfide, such as dust areas, utilities and yards, subject to the plant's own classification. Each location needs a decision by the safety officer.
It uses a different closed-loop solvent system, so the gas hazard is different from carbon disulfide. We do not state the details of the plant's classification, which belongs to Lenzing.
Tell us the site, the zone and gas group, and roughly how many handsets. The SAMS team replies by email with the datasheet and the certification schedule for Austria. The IS-04Z1 is pre-launch and certification is in progress, so there is no list price yet; indicative pricing is issued in writing against a stated quantity and site.
Tell us the zone, gas group and operator. We will send the datasheet and the certification schedule for your market.
