Steam indicator tape is one of the simplest tools in a sterilization department, and one of the most important. Applied across the closure of a wrapped tray or pouch, it does two jobs: it holds the pack closed, and its printed indicator changes colour when the pack has been exposed to the steam sterilization process. That single visual cue prevents processed and unprocessed packs from being mixed up on the shelf — the failure that most often puts a non-sterile instrument on a surgical tray.

Because it is applied to every pack, tape is also the first monitoring product staff learn to read. A tape that changes colour weakly, or peels in the sterilizer, undermines the whole system.

Key selection criteria

• Performance at your cycle parameters. The tape must respond in both gravity (121 °C / 20 min) and pre-vacuum (132–134 °C / 4–6 min) cycles if you run both.
• Clear, irreversible colour change. Diagonal indicator lines should go from light yellow to a uniform dark brown/black. Lines that fade back or look grey after storage are a sign of poor ink.
• Adhesion and clean removal. The tape should stick firmly to crepe paper, SMS non-woven and paper/film pouches through the cycle, then peel away without residue.
• Compliance. Ask for the ISO 11140-1 Type 1 classification, the manufacturer's ISO 13485 certificate and, for Europe, CE documentation.
• Reliable supplier. Consistent lot quality, defined shelf life and documented traceability matter as much as the product itself.

Understanding sterilization conditions

Steam sterilization is typically run at 121 °C (250 °F) for 15–30 minutes in gravity cycles, or at 134 °C (273 °F) for 3–5 minutes in pre-vacuum cycles. A Type 1 indicator is designed to react to the presence of saturated steam at these temperatures; it is not intended to measure the full exposure time, which is why a Type 4, 5 or 6 indicator is used inside the pack as well.

Adhesion and substrate considerations

Test any new tape on the materials you actually use — kraft crepe paper, SMS wrap, paper/film pouches and rigid containers if you tape those. Good adhesion during the cycle prevents the pack from opening in the sterilizer; clean removal prevents fibre tearing when the wrap is opened at the point of use. Apply the tape to a dry surface, press along its full length and avoid stretching it, which can lift the ends.

Compliance and quality standards

Choose products manufactured under a certified quality system and classified to the relevant standard: ISO 13485 for the manufacturer's quality management system, ISO 11140-1 for the classification of chemical indicators (Type 1 for process indicators), and CE marking where applicable.

Storage and usage tips

• Store rolls at 15–30 °C (59–86 °F), below 60–70 % relative humidity.
• Keep away from direct sunlight and from sterilant vapours.
• Rotate stock and use before the printed expiry date; unopened rolls usually have a three-year shelf life.
• Do not write over the indicator lines — write on the tape between them or on the pouch film.

Common purchasing mistakes

• Choosing the cheapest tape without checking the colour change at your own cycle.
• Assuming a tape suits all sterilants — steam, EO and plasma tapes use different inks.
• Ignoring adhesion on your packaging materials.
• Working with suppliers who cannot provide certificates or consistent lots.

Frequently asked questions

Conclusion

The right steam indicator tape helps your facility keep an efficient workflow, meet compliance requirements and, most importantly, protect patients. Consider your sterilization cycles, your packaging materials and the manufacturer's quality credentials, and you will select a tape you can rely on every day.

The Bowie-Dick test, named after the two Scottish microbiologists who described it in 1963, is a Type 2 chemical indicator test defined in ISO 11140-1 and specified in EN 285 / ISO 17665. It does not test sterility. It tests whether a pre-vacuum sterilizer removes air from the chamber effectively and whether the steam that replaces it penetrates a porous load quickly and uniformly.

Why air removal matters

Steam sterilizes by condensing on surfaces and transferring latent heat. Air trapped inside a pack forms a pocket that steam cannot enter, so the contents inside that pocket never reach sterilizing conditions. Pre-vacuum sterilizers pull a series of vacuums to remove air; a leaking door seal, a faulty vacuum pump or non-condensable gases in the steam supply all leave residual air behind. The Bowie-Dick test is designed to reveal exactly that.

How to run the test

1. Warm the sterilizer with an empty cycle at the start of the day.
2. Place a standard Bowie-Dick test pack (or a disposable test pack that conforms to ISO 11140-4) horizontally on the lowest shelf, above the drain, in an otherwise empty chamber.
3. Run the dedicated Bowie-Dick cycle: 134 °C for 3.5 minutes (never longer, or a weak fault may be masked).
4. Remove the pack and examine the indicator sheet immediately.

Interpreting the result

Documentation

File each test sheet, or a copy, with the date, sterilizer number, cycle number and operator. Most accreditation schemes require the Bowie-Dick record to be retained with the sterilizer log.

Conclusion

The Bowie-Dick test takes ten minutes each morning and catches the single most common cause of steam sterilization failure — trapped air. Combined with a Type 1 tape on every pack, a Type 4/5 indicator inside every pack and routine biological monitoring, it forms the backbone of a compliant monitoring programme.

Sterilization cannot be verified by inspecting the product, so we monitor the process instead. Chemical indicators respond to physical conditions — temperature, time, the presence of steam or gas — and give an answer in seconds. Biological indicators contain a known population of highly resistant spores (Geobacillus stearothermophilus for steam, Bacillus atrophaeus for EO) and answer the only question that ultimately matters: did the cycle kill? They need incubation, from 24 minutes for rapid-readout systems to 24–48 hours for conventional ones.

The six chemical indicator types

How they work together

• Every pack, every cycle: a Type 1 indicator outside and a Type 4, 5 or 6 indicator inside. The external indicator sorts processed from unprocessed; the internal one confirms sterilant reached the contents.
• Every day: a Bowie-Dick (Type 2) test in each pre-vacuum sterilizer.
• At least weekly, preferably daily, and with every implant load: a biological indicator in a process challenge device.

Advantages and limitations

Chemical indicators are inexpensive, immediate and pack-specific, but they infer lethality from physical conditions. Biological indicators prove lethality directly, but their result arrives after the load has been processed and they sample only the location where they were placed. Neither replaces the other; together with physical monitoring of the sterilizer printout they form the three pillars of sterilization monitoring.

Conclusion

Use chemical indicators for immediate, pack-by-pack confirmation and biological indicators for periodic proof of lethality. Kangde Med supplies Type 1 tapes and Type 4, 5 and 6 strips for steam, EO, plasma and formaldehyde cycles to fit this programme.

A sterile barrier system must let the sterilant in, keep microorganisms out, and allow aseptic opening. For steam, EO and formaldehyde, paper/film pouches and reels (medical-grade 60–70 g/m² paper with a CPP/PET film) are the standard choice. For hydrogen peroxide plasma, use Tyvek® or polypropylene non-woven. Confirm that the manufacturer states conformity with ISO 11607-1 and EN 868-5 and can provide test reports.

Sizing and loading

• Choose a pouch or cut a reel length that leaves at least 30 mm between the instrument and each seal.
• Fill pouches to no more than three-quarters of their volume; use gusseted reels for bulky sets.
• Place ring handles and hinged instruments open; point sharp tips away from the peel side and protect them with tip guards.
• Do not double-pouch unless the inner pouch is not folded and both are validated for the purpose.

Sealing

Heat seals should be continuous, at least 6 mm wide, with no channels, wrinkles or burn marks. Validate sealer temperature, pressure and speed for the material, and run a seal test regularly. Self-seal pouches must be folded along the perforation and pressed along the full length of the adhesive strip.

Labelling

Write on the film side of the pouch, outside the seal, or on the indicator tape — never on the paper, which is the microbial barrier. Record contents, sterilization date, sterilizer and cycle number, and operator.

Drying and cooling

Packs must be completely dry before they are touched. A wet pack wicks microorganisms through the paper and must be reprocessed. Allow packs to cool on the sterilizer cart in a draught-free area before moving them to storage.

Storage and shelf life

Store below 25 °C and below 60 % relative humidity, in closed cupboards or covered shelving at least 25 cm from the floor and away from sinks and vents. Shelf life is event-related: a pack remains sterile until an event compromises it — a torn or wet pack, a broken seal, crushing or excessive handling. Kangde Med recommends a validity of six months after sterilization under these conditions, with a visual inspection of every pack before it is opened.

Conclusion

Most sterility failures do not happen in the sterilizer; they happen at the packing table, the sealer and the storage shelf. Standardising materials, sizes and procedures — and training every member of the team on them — is the most effective investment a department can make.

ISO 11607 applies to industry, healthcare facilities and anyone who packages medical devices that are sterilized after packaging. Its purpose is to ensure that the packaging system maintains sterility until the point of use and allows aseptic presentation.

Part 1 — materials, sterile barrier systems and packaging systems

Part 1 requires that materials are demonstrated to be a microbial barrier, are compatible with the intended sterilization process, are free of toxic substances that could transfer to the device, are suitable for labelling, and are stable through storage. It also requires that the packaging system as a whole protects the device through handling and distribution, and that seal integrity can be demonstrated.

Part 2 — validation of forming, sealing and assembly processes

Part 2 applies to the process of making the pack: it requires installation, operational and performance qualification (IQ/OQ/PQ) of sealing equipment, definition of critical parameters such as temperature, pressure and dwell time, and routine monitoring. In a hospital CSSD this translates to validating and monitoring the heat sealer.

How EN 868 relates to ISO 11607

The EN 868 series gives detailed test methods and requirements for specific materials. EN 868-5 covers sealable pouches and reels of porous materials and plastic film — the classic paper/film pouch and reel. A pouch that conforms to EN 868-5 is generally used to demonstrate conformity of the material with ISO 11607-1.

What to ask your supplier

• A statement of conformity to ISO 11607-1 and EN 868-5 for each pouch and reel product.
• The manufacturer's ISO 13485 certificate.
• Test data: microbial barrier, seal strength, burst and peel tests, indicator performance.
• Lot traceability and shelf-life information.

Conclusion

ISO 11607 turns "the pack looks fine" into demonstrable evidence. Choosing packaging that is documented against ISO 11607-1 and EN 868-5, and validating your own sealing process to ISO 11607-2, closes the loop between the sterilizer and the operating table.

Decontamination, inspection and assembly, packaging, sterilization, cooling, storage and distribution — every CSSD follows the same one-way flow. Bottlenecks usually appear at the packing table and at the sterilizer unloading area. Start by timing each step for a typical tray and counting packs rejected at each point.

Standardise packaging

• Assign a reel width, length and pouch size to each instrument set and print it on the set list.
• Stock a small number of reel widths — six is usually enough — and use gusseted reels for bowls and deep sets.
• Use self-seal pouches only where a sealer is not available, to keep the seal process consistent.

Colour-code monitoring

When steam, EO and plasma sterilizers are used in the same department, choose indicator tapes and strips with clearly different colour changes for each sterilant, and store them in separate, labelled bins at the packing table.

Work instructions at the station

A laminated one-page instruction at each packing station — pouch sizing, indicator placement, sealing parameters, labelling — reduces variation when staff rotate.

Consumable stock control

Define minimum and maximum stock levels for every consumable, with lot numbers recorded on receipt. A single supplier for tapes, strips, pouches and reels simplifies ordering, documentation and training.

Review rejects weekly

Wet packs, torn pouches, incomplete indicator changes and failed seals each point to a specific cause — overloaded carts, wrong pouch size, poor steam quality or sealer drift. A short weekly review of the reject log is the fastest route to improvement.

Conclusion

Efficiency in the CSSD is not about speed for its own sake; it is about removing the variation that causes rework and risk. Standard packaging, clear monitoring and disciplined stock control deliver both throughput and patient safety.

A sterilizer that completes its cycle without an alarm has not necessarily sterilized its load. Air pockets, poor steam quality, overloading and incorrect packaging can all leave instruments non-sterile while the display reads "cycle complete". Monitoring provides independent evidence, for each cycle and each pack, that sterilizing conditions were achieved.

Physical monitoring

The sterilizer's printout or electronic record shows time, temperature and pressure for every phase. Operators should check it at the end of every cycle and sign it before releasing the load.

Chemical monitoring

• External (Type 1): indicator tape or pouch print on every pack — distinguishes processed from unprocessed.
• Internal (Type 4, 5 or 6): a strip inside every pack, placed where the sterilant is least likely to reach — confirms penetration.
• Bowie-Dick (Type 2): daily in every pre-vacuum sterilizer — confirms air removal.

Biological monitoring

Biological indicators containing resistant spores are the reference test of lethality. Run one in a process challenge device at least weekly, preferably daily, for each sterilizer, and with every load containing implants. Quarantine implant loads until the result is negative.

Documentation

For each cycle, record the sterilizer and cycle number, load contents, operator, physical parameters, external and internal indicator results and any biological indicator result. Retain records for the period required by your regulator — typically several years — so that any pack can be traced back to its cycle.

Conclusion

Monitoring is how a sterilization department proves, rather than assumes, that its instruments are safe. Kangde Med supplies the chemical indicators — tapes and Type 4, 5 and 6 strips for steam, EO, plasma and formaldehyde — that make up the everyday part of that programme.