5 Ways High-Performance Plastics are Redefining Manufacturing

Thermastock PVC strip curtains provide an effective thermal barrier while allowing safe pedestrian and vehicle access

Thermastock is Plastock's range of clear flexible PVC curtain strip — available as roll stock and as pre-assembled, ready-to-fit kits, with the core range held in UK stock and same or next-working-day despatch on stocked items.

This guide covers everything buyers, fabricators and facilities managers need to know: from choosing the right grade and measuring a doorway correctly to the physics of thermal barriers and the cost of getting the hanging system wrong.

CONTENTS

• PVC Strip Curtain, Ordered Online, Despatched Fast
• Thermastock at a Glance
• Grades and Variants - Choosing the Right Strip
• What Flexible PVC Actually Is
• Strip Dimensions - Getting the Size Right
• Suspension Systems and Installation
• Temperature Control and Energy Performance
• Markets and Applications
• Maintenance, Cleaning and Strip Replacement
• Why Thermastock?
• Compliance, Safety and Regulatory Context
• Troubleshooting - When Strip Curtains Underperform
• Supply, Stock and How to Order
• Specification Checklist
• Summary

1. PVC Strip Curtain, Ordered Online, Despatched Fast

If you need PVC strip curtain, the usual buying experience is one of two things: you either find a supplier selling bare 50m rolls with no guidance on sizing, rail or fixings, or you submit an enquiry and wait for someone to come back to you with a price. Thermastock was built to remove both of those problems. Strip, rail and fixing plates are competitively priced and listed online, in the sizes most doorways actually need, ready to order and if part of our stocked range, usually despatched the same or next working day.

That simplicity is the point. A buyer working out a doorway size at 4pm on a Thursday shouldn't need to email for a quote and wait until Monday to find out what it costs. With Thermastock, the price is on the page, and if the kit is in stock the order can be placed there and then. This is what has made the kit range popular in practice: clear pricing and fast despatch where stock allows, without the back-and-forth that strip curtain buying often involves elsewhere.

Thermastock is Plastock's range of flexible PVC curtain strip: clear crystal strip in rolls and ready-made kits, polar/freezer grade, ribbed grade, fire-retardant, and transparent coloured strip in roll form. For the most common doorway sizes, the kit covers everything needed — strip, stainless steel rail and fixing plates supplied together, ready to fit. A customer selects the kit for their doorway size, sees the price, orders online, and it is typically despatched the same or next working day, stock permitting. They attach the rail and cut the strip to final length on site. No measuring service required, no waiting on a quote.

Choose between continuous roll stock for bespoke installations or ready-made kits for the most common doorway sizes

It helps to know the difference between roll stock and kit before ordering. Roll stock is flexible PVC strip supplied as a continuous 50m reel, without rail or fixings — cut to whatever length the doorway actually needs, whether that is a standard warehouse height or something considerably taller. It is the raw material for a buyer who wants to specify their own hardware, hold stock for ongoing maintenance, or fit a doorway outside the kit range's standard heights.

A kit is a single pre-assembled product combining strip, stainless steel rail and fixing plates, ready to fit straight from the box, priced and ordered online in a couple of clicks. Thermastock kits are available now in clear crystal grade, in the specific sizes listed on plastock.co.uk. Polar and ribbed grades are supplied as roll stock at this stage; a buyer needing either of those grades assembles the installation from roll stock, rail and plates ordered as separate components. Buyers who need less than a full 50m reel should contact the Plastock team directly to discuss part-reel quantities and pricing.

For the simplest possible purchase, the clear crystal kit range covers the most common doorway sizes. For polar or ribbed grade, or a non-standard size, roll stock plus separately stocked rail and plates gives full flexibility.

Throughout this guide the product is referred to as Thermastock. The terms PVC strip curtain, clear flexible PVC, PVC door curtain, strip door, industrial strip curtain, cold room curtain, freezer curtain and chiller curtain are used interchangeably where relevant — because those are the terms buyers search for, and Thermastock is the answer to all of them.

Plastock Insight:
The strip curtain market still runs largely on bare rolls or price-on-application. A buyer who can see the price, pick the size, and order without waiting on a quote has a genuinely easier purchase than the market default — and that ease is what brings repeat business, not just the first order.

2. Thermastock at a Glance

A quick overview of the key features, supply options and performance characteristics of Thermastock

A rapid-reference summary for buyers and specifiers who need key facts before reading further.

3. Grades and Variants - Choosing the Right Strip

Choosing the correct grade ensures maximum performance and service life for each application

Grade selection is the most consequential decision in any strip curtain specification. It matters more than strip width, more than suspension system choice, and in most cases more than price. A standard-grade strip installed at a freezer door will become rigid and brittle within weeks. A ribbed strip specified for a light pedestrian doorway is over-engineered and unnecessarily expensive.

The relationship between grade and environment is direct: choose correctly and the curtain works invisibly for years; choose incorrectly and it fails visibly and quickly. The table below maps grades to their environments and primary performance properties. Thermastock launches with the core grades covering the majority of UK commercial and industrial applications.

3.1 Clear Crystal - The Foundation Grade

Standard clear crystal is the workhorse of the range. Its defining property is optical clarity: properly specified and installed, a clear crystal strip curtain is almost invisible, allowing personnel and vehicles to see through it clearly in both directions. This matters for safety — a forklift driver needs to see pedestrians on the other side of the opening before pushing through — and for the sense of openness that clear strip curtain preserves in a space where a solid door would not. Further widths in standard grade are planned beyond the current 200mm, 300mm and 400mm range — check here for the latest confirmed sizes.

Standard grade operates comfortably between approximately −15°C and +50°C. Below −15°C, the material begins to stiffen; below −25°C it can crack. This is not a failure of quality — it is the physics of the plasticiser system at low temperatures. The solution is polar grade, not a thicker standard strip.

3.2 Polar / Freezer Grade - Cold Environments

Polar grade flexible PVC is formulated with a plasticiser system that remains effective at temperatures standard grade cannot tolerate. Thermastock polar grade is rated to −25°C, confirmed initially in 300mm × 3mm (smooth), with a 300mm × 3mm polar-ribbed option also confirmed — both available in UK stock from August 2026. Where standard strip goes rigid and eventually cracks under movement at sub-zero temperatures, polar grade retains its flexibility, its clarity and its barrier performance down to this limit. It is the only correct specification for any cold room operating below approximately −5°C, and it is essential for freezer stores, blast-freeze chambers and refrigerated loading docks.

The consequences of misspecification here are both physical and financial. Rigid strips at a freezer door do not brush aside cleanly — they snap under forklift contact, they fail to re-close after pedestrian passage, and they allow warm, moist air to penetrate the cold space at every gap. The resulting refrigeration system overload is measurable in energy costs within days. Replacing a standard-grade curtain with polar grade is straightforward; running a sub-optimal refrigeration system for months before identifying the cause is not.

3.3 Ribbed Grade - High-Traffic and Forklift Environments

Ribbed PVC strip — referred to as "double rib" in Thermastock's production specification — has the same thermal and optical properties as standard crystal at the same temperature range. What it adds is a profile: the surface carries a series of raised ribs running along the length of the strip.

These ribs serve two distinct purposes. The first is mechanical. In a busy forklift doorway, adjacent strips are repeatedly pushed apart and allowed to return. Flat strips, particularly in warm or slightly humid conditions, can develop a tendency to cling together after contact — an effect sometimes called blocking. When strips cling, they resist separation under pedestrian traffic and reclose too aggressively around vehicle bodywork. Ribs hold the strip surfaces apart, virtually eliminating blocking.

The second benefit is durability. The ribs absorb contact and deflect impact across their raised profile rather than concentrating it on the flat face. Over a forklift cycle of thousands of passes per day, this reduces surface wear and extends the useful life of the curtain significantly compared with flat strip in the same environment.

Ribbed grade is confirmed in 200mm × 3mm, with a polar-ribbed combination also confirmed in 300mm × 3mm for cold environments with heavy traffic — both available in UK stock from August 2026.

3.4 Fire-Retardant Grade

Standard flexible PVC is a combustible material. It will ignite and burn when exposed to sufficient heat, and it does not self-extinguish. For most industrial and warehouse applications, this is an acceptable risk — managed through wider fire safety provisions in the building — but certain environments specifically require materials with improved fire performance.

Exhibition halls, large public entertainment venues, hospitality back-of-house areas, and some retail environments operated by major chains may require fire-retardant specification for any flexible curtaining. The requirement is usually driven by the venue operator's licence conditions, building regulations, or insurer requirements rather than a general statutory mandate.

Thermastock fire-retardant grade is formulated to reduce flame spread significantly compared with standard PVC. It has been independently tested by SGS (report ref. AJFTS26005894R01_EN, July 2026) to BS 2782-0:2011 Method 508A and is classified TP(b) under Approved Document B (Fire Safety), Building Regulations 2019 edition as amended 2020/2022/2025. Formal EN13501 classification is targeted for 2027. The ratings of the fire-retardant grade should be discussed with the relevant venue manager or fire officer before specification.

3.5 Transparent Coloured Strip

Transparent coloured strip retains the see-through property of clear crystal but adds a tint — typically red or yellow at the strip ends of a curtain, blue or green for zone demarcation. Its most common application is safety marking: coloured strips at the left and right edges of a curtain make the doorway boundary clearly visible to forklift drivers and pedestrians, reducing the risk of vehicles clipping the door frame. Coloured strips are also used to demarcate fire exit routes, zone off specific work areas, or simply add a visible identity to an entrance within a large industrial space.

Thermastock also offers a dark red welding-screen grade (300mm × 3mm) — a tint with a different purpose from the marking colours above. Rather than being for visibility, it is formulated to block the ultraviolet and infrared radiation emitted by welding arcs, protecting personnel outside a welding bay from arc flash exposure; see Section 9 for the full specification and rationale.

3.6 Thermastock Wide-Format Sheet — For Bespoke Widths and Large Openings

The 200mm, 300mm and 400mm widths covered above are extruded directly to those fixed sizes, which suits the great majority of doorways. Some installations call for something different — a bespoke strip width that doesn't match the standard range, or a single wider panel rather than several overlapping narrower strips. For these cases, Thermastock offers a wide-format flexible PVC sheet range as a standard part of the line-up, supplied as continuous sheet from 1000mm up to 1500mm wide, in thicknesses from 1mm up to 5mm, which can be cut down to whatever width an installation actually needs rather than being limited to the three standard extruded widths.

This is a genuinely different product from the extruded-to-width curtain strip described elsewhere in this guide, and it suits different jobs: oversized industrial doorways where a non-standard strip width works better than the nearest standard size, large viewing or screening panels where a single wide sheet is preferable to several overlapping strips, and any application where a bespoke width is the whole point of the enquiry. This is a standard part of the Thermastock range, but it is not held in stock — it is ordered in against each requirement. Contact the Plastock team to discuss a bespoke-width requirement and current lead time.

Wide-format sheet also sees regular use outside the doorway curtain itself. In fabrication, 3mm grey flexible sheet is welded up into flexible connectors that isolate vibration between fans, air handling units and ductwork — a role more commonly filled by PVC-coated fabric, but one this grade of sheet is also put to in practice. Clear wide-format sheet has its own separate set of fabrication uses: sneeze guards and protective screens at counters and workstations, sight windows and viewing panels on machine guards and equipment covers, and vertical or horizontal panels for greenhouse, patio and porch enclosures. In each case the sheet is cut and welded to the fabricator's own specification rather than supplied as a finished product — Thermastock provides the material, not the fabricated item.

Plastock Insight:
The single most common reason PVC strip curtains are replaced ahead of schedule is misspecification of grade, not product failure. Strips going rigid in cold, cracking at edges, or failing to resist repeated forklift contact are almost always the wrong grade for the environment — not inferior material. The correct grade, correctly installed, requires virtually no maintenance and should last for years in normal use

4. What Flexible PVC Actually Is

Most buyers of strip curtain never need to understand the chemistry of the material they are buying. They need it to be clear, flexible, durable, and compliant. But for buyers who need to specify compliance, justify purchasing decisions internally, or understand why one grade behaves differently from another, a grounding in the material itself is worth having.

4.1 PVC and Plasticisers - The Chemistry Behind Flexibility

PVC — polyvinyl chloride — is one of the most widely produced polymers in the world. In its natural state, once polymerised from vinyl chloride monomer, it is a rigid, relatively brittle material. The PVC used in window frames, drainage pipe, and rigid sheet is this base material with minimal modification: it is hard, dimensionally stable, and resistant to weathering.

Flexible PVC is the same polymer transformed by the addition of plasticisers during compounding. A plasticiser is a chemical added to PVC to increase the mobility of its molecular chains — effectively lubricating the polymer at the molecular level and allowing it to flex without fracturing. The higher the proportion of plasticiser in the compound, the softer and more flexible the resulting material. Strip curtain PVC typically contains a substantial proportion of plasticiser by weight, giving it the draping quality and impact recovery that makes it effective as a door barrier.

The choice of plasticiser matters both for performance and compliance. For decades, phthalate-based plasticisers — particularly DEHP and its relatives — were standard across the flexible PVC industry. They are effective and inexpensive, but several phthalates are now classified as substances of very high concern under REACH (the EU and UK Registration, Evaluation, Authorisation and Restriction of Chemicals regulation), and their use in many applications is restricted or prohibited. Modern UK and European flexible PVC strip for commercial and industrial use is formulated with non-phthalate alternatives — typically DOTP (dioctyl terephthalate) or DINCH — which deliver equivalent plasticising performance without the regulatory restriction. Thermastock's compound is confirmed as approximately 56% PVC resin, 42% DOTP plasticiser and 1% tin-based heat stabiliser, with the balance made up of lubricant. DOTP is a non-phthalate ester in widespread commercial use and is not classified as an SVHC (Substance of Very High Concern) under REACH.

Flexible PVC for strip curtain has a specific gravity of approximately 1.2 to 1.3, depending on plasticiser loading — meaningfully heavier than water (SG 1.0) but significantly lighter than rigid PVC pipe (SG approximately 1.4). This density is worth noting in the context of handling: a full-width strip curtain on a large industrial doorway carries real weight, and the rails and fixings supporting it must be specified accordingly.

 Thermastock compound uses a tin-based heat stabiliser rather than a calcium-zinc system. Tin stabilisers remain widely used across the European flexible PVC industry and are compatible with REACH; the older generation of concern for procurement teams is lead-based stabiliser, which Thermastock does not use.

4.2 The Extrusion Process and Why Strip Quality Varies

Flexible PVC strip curtain is manufactured by a continuous extrusion process. PVC compound — pre-blended with plasticiser, stabilisers, pigments and any specialist additives — is fed into an extruder and heated until it flows. It is then forced under pressure through a die whose profile determines the shape of the finished strip: width, thickness, and critically, edge profile.

The edge profile of an extruded strip matters more than it might appear. A strip with a square-cut, sharp edge presents a genuine risk to personnel in a busy doorway: flexible PVC at strip curtain densities has an SG of around 1.2–1.3, giving a 400mm × 4mm strip considerable mass and momentum when set in motion by a forklift. A sharp edge moving at speed is, in practical terms, a cutting hazard. Quality manufacturers extrude their strip with fully rounded edges as standard. The rounding is not cosmetic. It reduces the risk of skin laceration on contact and distributes impact stress across the edge profile, reducing the tendency for edge cracking under repeated flex. Thermastock's 200mm, 300mm and 400mm strip is confirmed extruded with rounded edges as standard across the range.

Rounded edges improve safety while reducing stress concentrations that can lead to premature cracking

Quality also varies at the compound level, in ways that are invisible on inspection but apparent in service. The uniformity of plasticiser distribution through the PVC matrix determines how consistently the strip flexes — whether it recovers evenly after being pushed aside or develops permanent deformation. Stabiliser selection affects how the material performs under UV exposure and elevated temperature over its service life. The production controls during extrusion — temperature profile, die condition, haul-off speed — determine wall consistency and the absence of internal stresses that could lead to premature cracking.

These are not abstract concerns. The strip curtain market includes products at a wide range of price points, sourced from manufacturers across Europe and beyond. The difference between a strip that serves for three years and one that begins to yellow, stiffen and crack within twelve months is almost always in the compound specification and extrusion quality, not in the visible appearance of the finished product.

Plastock Insight:
Flexible PVC is one of the most tightly regulated plastics in the European and UK market. A strip curtain product that cannot demonstrate REACH compliance and non-phthalate formulation is not a viable specification for food environments, pharmaceutical facilities, or any public venue with an astute procurement team. Thermastock's material is REACH-compliant with a Declaration of Conformity available from the manufacturer; contact the Plastock team for a copy.

5. Strip Dimensions: Getting the Size Right

More specification errors in strip curtain arise from wrong sizing than from any other cause. Most are entirely avoidable with a straightforward calculation. This section provides the framework.

5.1 Standard Width and Thickness Combinations

Thermastock clear flexible PVC strip is available in three standard width and thickness combinations, covering the full range of pedestrian, light-vehicle and heavy-vehicle applications:

• 200mm × 2mm — standard for pedestrian doorways, light vehicle access, and internal partition applications
• 300mm × 3mm — suited to moderate-traffic forklift operations and larger openings
• 400mm × 4mm — recommended for heavy forklift and pallet truck traffic, and for wide industrial doorways

The width and thickness are paired deliberately. A thinner strip in a wide format would lack the stiffness to hang and recover correctly; a very thick narrow strip would create excessive resistance to pedestrian movement. The 200/2, 300/3 and 400/4 combinations reflect decades of established industry practice and the practical requirements of each traffic type.

Thermastock does not currently stock 100mm strip. For applications requiring narrower strips — typically very light internal partitioning or specialist uses — this should be confirmed with the Plastock team, as it may be available to order.

5.2 Overlap - The Detail That Determines Performance

A strip curtain is not a solid barrier. It is a series of overlapping flexible strips, and it is the overlap that creates the seal. Adjacent strips cover each other by a defined amount — and this overlap is what prevents air, dust, insects and noise from passing freely through the gaps between strips. Insufficient overlap is the single most common cause of underperforming strip curtain installations; it is invisible at the point of ordering and only becomes apparent when the heating bill arrives.

The standard for good practice is a minimum overlap of approximately one-third of the strip width. For cold room and freezer applications, 50% overlap — or a double-layer twin-track system — is often appropriate. The calculation for the number of strips required is straightforward:

• Number of strips: = (Doorway width ÷ Strip width) × 1.5, rounded up to the nearest whole number.

This gives approximately 50% overlap per strip. The worked examples below cover three common doorway sizes to illustrate the calculation in practice.

The roll length required is the number of strips multiplied by the doorway height, with a small additional allowance for trimming. For clear crystal at a standard doorway size, selecting the matching Thermastock kit removes this calculation entirely — strip count and rail length are pre-configured. For polar or ribbed grade, or any non-standard size, the calculation above applies to roll stock ordered with separate rail and plates.

Common mistake: Measuring the doorway width and dividing by strip width to get the number of strips — without any overlap allowance. This produces a curtain with strip edges just touching, no overlap, and essentially no barrier performance. Always apply the ×1.5 multiplier above.

Plastock Insight:
The overlap specification is where many first-time installations fail quietly. Strips can be perfectly correct in grade and width, but if they are spaced too far apart, the thermal or hygienic barrier they are meant to create simply does not exist. When a cold room seems to be working harder than expected after a new curtain installation, the overlap is the first thing to check

5.3 Doorway Height and Strip Length

Strip length is simply the doorway height plus a modest allowance for fixing at the top (typically 100–150mm above the opening, to allow the rail to sit above the lintel) minus a small clearance at the base. The standard practice is to leave a 10–20mm gap between the bottom of the strips and the finished floor level. This gap serves three purposes: it prevents strips dragging on uneven floors, it reduces pick-up of floor contaminants onto the strip surface, and it eliminates the mechanical stress at the base of the strip that would otherwise be introduced by ground contact.

For applications where the floor seal is critical — blast-freeze chambers, for example, or applications where draught exclusion at floor level is a priority — this gap should be discussed specifically, as the installation geometry may need to be adjusted.

 Thermastock strip is available as a continuous 50m roll, cut to whatever finished height a doorway actually needs — in practice this means openings up to several storeys are just as achievable as a standard warehouse doorway, not just the heights the kit range happens to cover. For the great majority of standard doorway heights, though, cutting and hooking a roll on site is more than most buyers need to do: clear crystal in the most common heights (2m, 3m, 4m and 5m) is available as a pre-assembled kit, with strip, rail and plates supplied together and ready to fit. Polar and ribbed grades, and any non-standard or oversized height, are supplied as roll stock with rail and plates ordered separately, typically enabling same or next-working-day despatch and on-site final trimming to the exact finished height.

6. Suspension Systems and Installation

The strip is only as good as the system holding it. The most common cause of strip curtain failure in service is not strip degradation — it is a rail or fixing that works loose under repeated impact and eventually deposits the curtain on the floor. A heavy industrial curtain falling from its rail is not a trivial incident: the steel rail, fixings and the weight of the PVC combined represent a genuine hazard to anyone passing through the doorway at that moment.

6.1 Suspension System - Rail and Plate

Individual fixing plates allow damaged strips to be replaced without dismantling the entire curtain.

The suspension system uses a stainless steel fixing plate riveted or bolted to the top of each strip, which hooks onto a stainless steel rail fixed above the door opening. The plate covers the strip head and is secured to the rail, giving a positive fixing that resists the pull-away force of a forklift catching the curtain at the top of its stroke.

Thermastock's plate is a stainless steel front plate — there are no through-bolts in the standard system, keeping the installation clean and the fixing profile low. The system is also straightforward to maintain: because each strip is fixed individually, a single worn or damaged strip can be unhooked and replaced without disturbing the rest of the curtain or removing the rail — useful for large estate operations where strip replacement is a routine activity. 

A concern sometimes raised with plate systems is what happens if a plate were to detach unexpectedly — a steel plate with a row of strips attached falling from rail height is not a trivial hazard. In practice, this does not occur. Confirmation from Thermastock's manufacturer is unambiguous: in their experience across many years and a large number of installations, the strip curtain will break under extreme forklift impact before the rail or plate ever dislodges. No claims relating to rail or plate detachment have been recorded. The mechanics support this: a fixing correctly made into structural substrate holds far more resistance to pull-away force than the PVC strip it is securing. Drivers are also expected to reduce speed when passing through a curtained doorway, which further limits impact loading in practice.

6.2 Installation Checklist

• Measure the door opening width and height — the clear opening, not the frame.

• Calculate strip count using the ×1.5 overlap method (see Section 5.2), or select the matching Thermastock kit directly if ordering clear crystal in a standard size.

• Check the lintel or wall above the opening: the rail, fixings and full curtain weight must be supported. For large industrial curtains this is not trivial — verify fixings into masonry or steel structure as appropriate.

• For cold room and freezer installations: use stainless steel rail (grade 304 as minimum; grade 316 where wash-down chemicals or high humidity are present). Galvanised steel will corrode rapidly in these environments. Please ask a member of staff if 316 is required.

• Leave 10–20mm clearance between strip bases and the floor.

• After installation, check the overlap along the full width — hold a light source on one side and check for light transmission gaps on the other. Visible light gaps indicate insufficient overlap.

• For plate systems: torque fixings to the rail manufacturer's specification and check periodically, particularly in the first month after installation when forklift impact may settle the fixing.

Plastock Insight:
Over-engineering the wall fixing is rarely a mistake. The rail, fixings and PVC combined on a large forklift doorway can easily exceed 20–30kg. A fixing that 'looks about right' for a domestic door is not the same thing as a fixing rated for repeated impact loading in an industrial environment.

7. Temperature Control and Energy Performance

The primary reason most commercial and industrial premises install strip curtain is straightforward: to stop paying to heat or cool a building through its open doorways. The energy case is compelling, the physics are simple, and the return on investment is usually measured in months rather than years.

7.1 How Strip Curtains Create a Thermal Barrier

An unguarded doorway between a heated or temperature-controlled space and an uncontrolled area creates two simultaneous air movements. Warm air — being less dense — rises and exits through the upper portion of the opening. Cooler, denser air enters through the lower portion. This convective exchange continues for as long as the opening exists and a temperature differential is present. The rate of exchange is determined by the size of the opening, the temperature difference, and the degree of air movement on either side.

In a warehouse or food production facility with multiple large doorways between heated and unheated zones, the cumulative effect of this convective exchange can represent a very large proportion of the annual heating cost — often the single largest controllable element of the energy bill. PVC strip curtains interrupt this exchange. They do not eliminate it completely — the strips flex and separate under pedestrian and vehicle movement — but a well-specified curtain with adequate overlap reduces air exchange by approximately 60–70% for a single-layer system and 70–85% for a twin-track double-layer installation.

For cold rooms and refrigerated stores, the benefit is expressed differently: not as a reduction in heating demand, but as a reduction in the work the refrigeration plant must do to maintain its set temperature. Every cubic metre of cold air that escapes through an unguarded cold room entry must be replaced by additional refrigeration run time. Independent testing by engineering firms in controlled cold-storage environments has recorded reductions in refrigeration energy consumption of around 24% from correctly specified strip curtain installation.

7.2 Cold Rooms and Freezer Stores

The cold room application is where strip curtain specification has the highest consequence. Standard grade PVC at sub-zero temperatures does not fail gradually — it fails abruptly. The plasticiser system that gives the strip its flexibility becomes progressively less effective as temperature drops below approximately −10°C. The strip stiffens, begins to resist movement, and eventually cracks along its length when pushed by a pedestrian or struck by a forklift. A cracked or rigid strip is not a thermal barrier — it is a gap in the wall.

Polar grade is specifically compounded to remain flexible at cold-room and freezer temperatures. The plasticiser system is selected and loaded to maintain molecular chain mobility at temperatures standard grade cannot tolerate. The visible result is a strip that brushes aside and recovers identically at −20°C as it does at +15°C. The thermal result is a cold room curtain that continues to perform throughout the operating cycle without degradation.

A further consideration at freezer entries is the geometry of the installation. Where warm, moist ambient air meets the cold surface of the strips, condensation and ice formation can occur. Positioning the curtain slightly inside the opening — rather than flush at the door face — allows a small buffer zone that reduces the temperature gradient at the strip surface. A double-layer installation with a small gap between the two curtain positions is the most effective approach for very cold stores where ice build-up at the entry is a persistent problem.

7.3 Energy Saving: What the Numbers Look Like

The market commonly references energy savings of 25–40% on heating or cooling costs attributable to strip curtain installation. These figures are directionally accurate but depend heavily on how frequently the doorway is used, the temperature differential, the building's baseline insulation, and whether the curtain is correctly specified and maintained. They should be treated as a realistic range for a well-installed system, not a guarantee.

The table below provides illustrative investment recovery scenarios for three typical commercial applications. Strip curtain material costs should be confirmed directly with Plastock; energy cost assumptions use an indicative UK commercial electricity rate of approximately 25p/kWh and gas rate of approximately 7p/kWh.

The pattern across all three scenarios is consistent: the annual energy saving comfortably exceeds the cost of the curtain within the first year of operation. In the cold room scenario, the saving is concentrated in refrigeration run cost rather than space heating — and the additional benefit of reduced temperature fluctuation inside the cold room extends the service life of refrigerated goods and reduces product waste.

Plastock Insight:
A PVC strip curtain is not a substitute for a door. It is a complement to a well-managed building envelope that reduces air exchange during the periods when a door cannot practically be kept closed. In high-traffic operations — loading bays, cold room entries, processing line boundaries — it is frequently the only realistic thermal barrier available, and its cumulative energy impact over a full year is consistently underestimated at the point of purchase.

8. Markets and Applications

Thermastock provides practical doorway solutions across a wide range of commercial and industrial applications

Clear flexible PVC strip curtain has one of the broadest application profiles of any building material. The combination of visibility, flexibility, easy installation and low cost makes it effective wherever a controlled separation is needed without the barrier of a solid door. The table below maps the major UK market sectors to typical installation locations and recommended Thermastock grades.

8.1 Food and Beverage

The food and beverage sector is the largest single market for flexible PVC strip curtain in the UK, and the most demanding in terms of specification. The requirements are multiple and, on occasion, in tension with each other: a cold room entry needs to be cold-resistant and hygienic; a processing line separation needs to be transparent enough for supervisory oversight while providing a physical barrier against cross-contamination; a loading dock door needs to be robust enough for forklift traffic while maintaining the cold chain during vehicle movements.

Hygiene is the primary operational concern. Strip curtain in food environments is in near-constant contact with personnel, packaging, equipment and occasionally product. It must be easy to wipe clean, resistant to the cleaning chemicals used in the facility, and free from crevices or surface features that can harbour bacteria. Flexible PVC strip — smooth, non-porous, and capable of being wiped down with standard food-safe detergents — meets these requirements in its standard form. The strip can be removed and replaced if contamination occurs; this replaceability is a genuine operational advantage over alternatives.

Direct food contact — where strip curtain physically touches exposed product — requires a specifically formulated food-contact grade compliant with EU Regulation 10/2011 and the broader framework of Regulation (EC) 1935/2004 governing food-contact materials. This grade uses raw materials authorised for food contact, is formulated for low migration of plasticiser and additives, and is supplied with a Declaration of Compliance confirming its regulatory status. Thermastock offers food-contact grade through Plastock's wider supply network, available on application. For applications in abattoirs, fishmongers, open-produce cold rooms and similar environments where direct product contact cannot be excluded, contact the Plastock team to specify and confirm documentation. For the large majority of food-sector applications — cold rooms, loading docks, separation between ambient and chilled zones — Thermastock clear crystal is entirely appropriate without food-contact certification.

For the large majority of food-environment applications — cold rooms, loading docks, separation between ambient and chilled zones, back-of-house doorways in retail and hospitality — standard clear crystal or polar grade is entirely appropriate and does not require food-contact certification. The distinction is between incidental proximity to food (which standard grade handles without issue) and direct contact with exposed product (which requires food-contact grade specifically).

Polar Grade PVC remains flexible at temperatures down to approximately –25°C, making it suitable for cold storage and freezer environments

8.2 Warehousing and Logistics

Warehousing and logistics is the second-largest market for PVC strip curtain, driven by a combination of energy regulation, operational efficiency and the physical realities of loading bay management. A fully open loading bay door — necessary during vehicle movements — is one of the most energy-inefficient features in a heated warehouse. The opening is typically large (3m × 3m to 5m × 4m is common), the temperature differential between the heated warehouse interior and the external loading environment can be 15–25°C in winter, and the door may be open for extended periods during busy operational periods.

Strip curtain installed behind the dock leveller allows vehicles to enter and exit freely while maintaining a significant portion of the thermal barrier during the loading cycle. The strip curtain does not replace the outer dock door — it supplements it, providing separation during the period when the outer door is open and the vehicle is backed against the bay. In practical terms, this is often the majority of the day.

Grade selection for warehousing depends on whether the warehouse is temperature-controlled. For ambient-temperature warehouses where the primary benefit is draught exclusion and heating cost reduction, standard clear crystal at the appropriate width is the correct specification. For cold-store warehouses — ambient to 0°C to +5°C — polar grade should be confirmed for all dock door applications. For heavy forklift operations on any door, ribbed grade extends service life meaningfully compared with flat strip. Published comparisons from suppliers in the category indicate that ribbed strip in a high-forklift-traffic environment can outlast flat strip by a factor of two to three in terms of cycles before requiring replacement — a material difference in the operational cost of maintaining the curtain.

8.3 Retail and Supermarket

Retail and supermarket applications divide into two distinct zones: customer-facing chiller aisles, and back-of-house cold rooms and stock areas. The requirements in each are different, and the specification reflects that.

In customer-facing chiller aisles, particularly in supermarkets and food retailers, strip curtain is used on chiller display cabinet doors and at the entry points to walk-in chillers. Optical clarity is paramount — a strip that yellows, hazes or develops surface marks will be noticed by customers and will be replaced. Standard clear crystal 200mm strip is almost universal in this application, chosen for its visibility and the relatively light pedestrian traffic it experiences. Cleaning frequency is higher in retail than in most industrial environments, as strips in food retail are expected to be maintained to a visible standard of hygiene rather than simply a functional one.

Back-of-house applications are more demanding. Stock room cold rooms serving a busy supermarket may see dozens of staff movements per hour during peak periods, plus the regular passage of roll cages and hand pallet trucks. The door geometry is often constrained — a narrow opening between the shop floor and the stock area — making 200mm clear crystal the natural choice for width. Polar grade should be specified wherever the cold room operates below approximately 0°C. Replacement frequency in retail is notably higher than in industrial settings, partly because cleaning regimes can accelerate surface degradation if incompatible products are used. Holding Thermastock replacement roll stock allows individual strips to be cut and replaced in minutes, keeping the cold room barrier intact without waiting for a made-to-measure replacement order.

8.4 Manufacturing and Industrial

Manufacturing environments cover an enormous range of applications, from light assembly shops to heavy process industries, and the strip curtain specification varies accordingly. The common thread is separation: between temperature zones, between production areas with different contamination requirements, between noisy and quieter spaces, or simply between a controlled area and general circulation.

In machine shops and fabrication bays, strip curtain provides a practical, low-cost boundary that allows materials and personnel to move freely while reducing the transmission of swarf, dust, coolant mist and noise. Standard clear crystal in 300mm or 400mm width is typical for forklift access points; 200mm suits pedestrian-only internal doorways.

Welding bays present a specific consideration. Standard clear PVC transmits ultraviolet and infrared radiation — the same radiation emitted by welding arcs that requires welders to wear face protection. A standard clear strip curtain across a welding bay opening does not protect personnel outside the bay from arc flash exposure. For welding environments, a welding-screen grade of strip should be specified rather than standard clear. This is a distinct product from general-purpose tinted strip. Thermastock welding-screen grade is a dark red tint (300mm × 3mm), available in UK stock from August 2026 — contact the Plastock team to discuss availability and lead time. Food-contact and other specialist grades remain available through Plastock's wider supply network on application (POA).

8.5 Agriculture and Equine

Agricultural and equine environments are among the most demanding for flexible PVC strip curtain, and among the most underserved in terms of specification guidance. A barn entrance or stable doorway exposes strip curtain to conditions that would not be present in a typical industrial installation: direct UV exposure from sunlight, temperature extremes from below freezing in winter to well above ambient in a south-facing barn in summer, physical contact from livestock, and the presence of ammonia and organic matter that can accelerate surface degradation.

For outdoor or semi-exposed barn entrances, polar grade is worth considering even where the primary purpose is not temperature control — the improved low-temperature flexibility means the strip continues to function correctly in hard frosts, when a standard-grade strip may go rigid enough to resist a horse pushing through. Ribbed strip is a sensible choice wherever livestock will be in direct contact with the curtain: the ribbed profile is more forgiving of animal movement than flat strip, and the mechanical durability under repeated contact is meaningfully higher.

8.6 Healthcare, Pharmaceutical and Clean Environments

Healthcare and pharmaceutical applications are the most compliance-sensitive in the strip curtain market. A strip curtain used as a boundary in a hospital corridor, a pharmaceutical manufacturing facility or a cleanroom environment must satisfy procurement teams that it does not introduce contamination risk — chemical, particulate or microbial.

For most healthcare corridor and zone-boundary applications, standard clear crystal PVC is appropriate: it is non-porous, easy to wipe clean, and does not shed fibres or particles under normal use. The relevant question for NHS procurement and pharmaceutical QA teams is typically the compliance documentation. Thermastock can supply a REACH Declaration of Conformity confirming non-phthalate (DOTP) formulation — the document that converts a technically suitable product into a specifiable one in regulated environments.

For cleanroom boundaries and pharmaceutical manufacturing zones, confirm any specific grade or compliance requirements with the Plastock team before ordering.

8.7 Public Venues and Events

Exhibition halls, conference centres, large hospitality venues and similar public buildings present a specific challenge: fire compliance. Most large public venues in the UK operate under a premises licence that includes conditions on the use of combustible materials in certain areas. Back-of-house areas in large event venues — catering loading bays, temporary storage areas, hospitality kitchens — frequently have specific material requirements driven by the venue's fire risk assessment or licence conditions.

Standard clear PVC strip is combustible and should not be specified in these environments without checking the venue's requirements. Thermastock fire-retardant grade has been independently tested by SGS (report ref. AJFTS26005894R01_EN, July 2026) to BS 2782-0:2011 Method 508A and is classified TP(b) under Approved Document B (Fire Safety), Building Regulations 2019 edition as amended 2020/2022/2025 and provides a compliant alternative to standard PVC strip. Always check with the venue's fire officer or facilities manager before specifying any grade of flexible PVC in a back-of-house area with a material compliance requirement.

8.8 Automotive and Workshop

Automotive workshops, vehicle paint facilities and commercial vehicle service centres use strip curtain principally for bay separation: dividing working bays from each other, separating a spray booth from a preparation area, or creating a barrier at the workshop entrance that vehicles can drive through without the delay of operating a solid door.

Standard clear crystal 300mm or 400mm strip suits most vehicle-passage applications. The width choice is determined by vehicle size: a bay serving cars and vans comfortably uses 300mm; a bay serving HGVs or large agricultural vehicles may need 400mm for adequate barrier performance and good strip recovery after wide-vehicle passage.

Paint spray environments require specific attention. Standard clear PVC is not solvent-resistant, and spray booth atmospheres containing VOC-based paints and thinners can cause rapid surface crazing and degradation of standard strip. For spray booth applications, confirm requirements with the Plastock team.

9. Maintenance, Cleaning and Strip Replacement

One of the most practically significant advantages of flexible PVC strip curtain over solid or powered door alternatives is the simplicity of its maintenance. There are no moving mechanical parts. There is no motor to service, no sensor to calibrate, no hydraulic system to maintain. The entire maintenance regime reduces to: keep it clean, and replace individual strips when they show visible deterioration.

9.1 Cleaning

Standard Thermastock clear PVC strip can be cleaned with a damp cloth and a mild, non-abrasive detergent. The strip should be wiped from top to bottom, with particular attention to the edges where contamination accumulates most rapidly in busy environments. After cleaning, residual detergent should be rinsed off to prevent surface film build-up that can reduce optical clarity over time.

What to avoid: solvent-based cleaners, acetone, MEK, strong alkalis, and abrasive pads or cloths. Any of these will cause the PVC to craze, cloud, or soften. In food environments, cleaning agents must be confirmed as compatible with PVC and appropriate for the food hygiene standards in operation at that facility. Chlorine-based sanitisers at normal concentrations used in food production are generally compatible with PVC, but should be rinsed off rather than left in contact with the strip surface.

Cleaning frequency depends on the environment. In a cold room accessed multiple times per hour by personnel in outdoor clothing, daily cleaning of the strip surfaces is reasonable. In a light-use internal partition application, weekly cleaning is adequate. The test is visual: if you can see contamination on the strip surface, clean it.

9.2 Inspecting for Wear

Flexible PVC strip wears from the edges inward and from the base upward. The most common signs of a strip approaching replacement are:

• Yellowing or hazing of the clear surface (UV or heat degradation); cracking or splitting along the length of the strip (grade misspecification, UV damage, or end of service life)
• Tearing at the top fixing holes (over-tightening of plate fixings, or strip being pulled by forklift impact rather than flexing cleanly)
• A permanent curl or set in the strip that prevents it from hanging straight (heat distortion, usually from proximity to a heat source or from being rolled too tightly in storage).

None of these conditions requires replacing the entire curtain. In a hook-on system, a single deteriorated strip is removed from the rail and a replacement cut from Thermastock roll stock in under five minutes. In a plate system, the plate covering that section is removed, the strip replaced, and the plate re-fixed. Holding a 50m roll of Thermastock strip on site for ongoing maintenance is a straightforward operational decision that eliminates the lead time and minimum order concerns of ordering individual replacement strips.

Plastock Insight:
The economics of strip replacement are consistently underestimated at the point of purchase. A curtain that functions correctly is free to operate. A curtain with one or two degraded strips that are not replaced costs money every day through the thermal or hygienic gap they leave — often far more than the cost of the replacement strip

9.3 When to Replace the Whole Curtain

Individual strip replacement is the right response to localised wear. Whole-curtain replacement makes sense when: more than a third of the strips show visible deterioration simultaneously (usually a sign that the original installation has reached end of life, or that grade misspecification has caused systematic failure); the rail or fixing system has been damaged by impact and requires removal; or the doorway dimensions have changed due to building modification.

A well-specified Thermastock installation in a standard warehouse application — standard grade, correct overlap, hook-on rail, no extreme temperature or chemical exposure — should provide several years of service before whole-curtain replacement becomes necessary. In high-forklift-traffic environments with ribbed grade, the service life is similarly extended. In cold rooms with polar grade and correct double-overlap specification, the curtain should outlast most operational reviews without requiring attention beyond routine strip-by-strip replacement as individual strips reach their service life.

10. Why Thermastock?

Strip curtain is not a product most buyers think about until they need it. When they do, they need it quickly, in the right specification, from a supplier they already trust. Thermastock is built around that reality: depth of stock, simplicity of ordering, and the convenience of sourcing strip curtain alongside every other clear plastic material from a single Plastock account.

For buyers who already work with Plastock, Thermastock is not a reason to evaluate a new supplier. It is a reason to consolidate strip curtain purchasing into an existing relationship that already works. For buyers new to Plastock, the strip curtain range is a natural starting point into a broader materials partnership covering acrylic, polycarbonate, foam and more.

Plastock Insight:
The buyer who needs PVC strip curtain and already orders acrylic or polycarbonate from Plastock does not need a second supplier. They need to know that Thermastock exists — and that it can usually be ordered alongside everything else on the same account.

11. Compliance, Safety and Regulatory Context

Compliance questions are among the first a serious procurement team will ask about any material going into a food, healthcare or public-venue environment. This section sets out the regulatory landscape for flexible PVC strip curtain in the UK and where Thermastock currently sits within it.

11.1 REACH and Non-Phthalate Formulation

REACH — Registration, Evaluation, Authorisation and Restriction of Chemicals — is the primary chemical safety regulation governing materials placed on the UK and EU market. Under REACH, a number of phthalate plasticisers formerly standard in flexible PVC have been classified as Substances of Very High Concern (SVHCs) and restricted or prohibited in many applications. The most significant for strip curtain are DEHP, DBP, BBP and DIBP, which are restricted under REACH Annex XVII.

Modern flexible PVC strip curtain for commercial and industrial use should be formulated with non-phthalate plasticisers — typically DOTP, DINCH or similar — and should be able to supply a Declaration of Conformity confirming REACH compliance on request. This is now a standard expectation in food, healthcare and pharmaceutical procurement, and is increasingly standard in general commercial tendering. A signed REACH Declaration of Conformity is available confirming compliance with EU Regulation 1907/2006: that no substance on the SVHC candidate list is present above 0.1% weight by weight per article, and that no substance appears on the Annex XIV (authorisation) or Annex XVII (restriction) lists.

Thermastock's compound is confirmed non-phthalate, using DOTP plasticiser and a tin-based stabiliser. A REACH Declaration of Conformity is available from the manufacturer; contact the Plastock team for a copy at the time of order.

11.2 BS2782 and the TP(b) Fire Classification

BS2782 is the British Standard covering methods of testing plastics. Thermastock's fire-retardant grade has been independently tested by SGS (report ref. AJFTS26005894R01_EN, July 2026) to BS 2782-0:2011 Method 508A and is classified TP(b) under Approved Document B (Fire Safety), Building Regulations 2019 edition as amended 2020/2022/2025.

This flame-retardancy rating is commonly specified for curtaining and screening materials in commercial and public buildings. This documentation supports procurement processes that require evidenced performance claims rather than supplier-stated specifications, and is separate from the EN13501 classification targeted for 2027 (see Section 11.3). Check plastock.co.uk or contact the Plastock team for the current availability of test reports.

11.3 Fire Classification (EN13501 / FR Grade)

Standard flexible PVC is combustible. EN13501-1 is the European classification system for the reaction to fire of construction products, covering flame spread, smoke production and burning droplets. Classification B-s3,d0 or better is commonly required for curtaining materials in public venues and large commercial buildings. The equivalent French M classification system (M1, M2, M3, M4) applies in French-specification projects.

Thermastock fire-retardant grade is formulated to reduce flame spread. It has been independently tested by SGS (report ref. AJFTS26005894R01_EN, July 2026) to BS 2782-0:2011 Method 508A and is classified TP(b) under Approved Document B (Fire Safety), Building Regulations 2019 edition as amended 2020/2022/2025. Formal EN13501 classification targeted for 2027. Until certification is issued and documented, the fire-retardant grade should not be specified for applications requiring a formally rated classification — check plastock.co.uk for current status, or contact the Plastock team to confirm the latest position before specifying.

11.4 Food Contact — EU Regulation 10/2011 and 1935/2004

Where PVC strip curtain may come into direct contact with food — in abattoirs, open-produce cold rooms, fish processing facilities, or similar environments — the material must comply with EU Regulation 10/2011 on plastic materials in contact with food, within the broader framework of Regulation (EC) 1935/2004. Compliance requires that the compound uses only authorised raw materials, that migration of plasticiser and additives stays within defined limits, and that a formal Declaration of Compliance is available.

Thermastock offers food-contact grade through Plastock's wider supply network, available on application. For applications requiring direct food contact with exposed product, contact the Plastock team to specify and confirm documentation. Thermastock clear crystal is suitable for the large majority of food-environment applications — cold rooms, loading docks, back-of-house zones — where the curtain is in proximity to food but not in direct contact with exposed product.

11.5 RoHS

RoHS — Restriction of Hazardous Substances in Electrical and Electronic Equipment — applies primarily to PVC used in electronics manufacturing and equipment. Some commercial procurement teams apply RoHS conformity requirements broadly across all materials. Confirm RoHS compliance status with the Plastock team if this is a specific procurement requirement.

12. Troubleshooting - When Strip Curtains Underperform

Most strip curtain performance problems have straightforward causes and equally straightforward remedies. The table below covers the most common failure presentations and their solutions.

Plastock Insight:
The overwhelming majority of strip curtain complaints trace back to one of two root causes: the wrong grade for the environment, or insufficient overlap. Both are specification decisions made before installation. A correctly specified, correctly installed Thermastock curtain typically requires very little reactive maintenance.

13. Supply, Stock and How to Order

Thermastock is available from UK stock with same or next-working-day despatch on stocked items in most cases. Actual delivery timing depends on courier network, location and order cut-off time — check plastock.co.uk for the current estimate at the time of order. The range is available in two formats: pre-assembled ready-made kits, and roll stock ordered with rail and plates as separate components.

13.1 Ready-Made Kits (Clear Crystal)

The Thermastock ready-made kit is one of the most straightforward ways to buy strip curtain on the UK market. Each kit contains everything needed for a complete installation, pre-assembled: flexible PVC strip in clear crystal grade, cut to a standard length, a 304 stainless steel rail, and stainless fixing plates — typically despatched the same or next working day, stock permitting. Kits are available only in the specific sizes and configurations listed on plastock.co.uk; they are not a made-to-measure service, and they do not currently extend to polar or ribbed grade. Kits are offered in standard curtain lengths from 2m to 5m, across all three width and thickness combinations, in clear crystal grade. The buyer selects the kit that matches or slightly exceeds their door height, hangs the strips from the rail, and cuts to the exact finished height on site using a straight-edge and a sharp knife — no specialist tools, no measuring service, no waiting for made-to-measure production. The sizing tables and guides in this article give everything needed to calculate the right kit for any standard doorway. Rails are stocked in three lengths (approximately 1m, 1.2m and 1.5m) to suit a range of opening widths; for very wide openings, rail sections are combined. For polar or ribbed grade, or any size outside the standard kit range, see Section 13.2 below.

Thermastock is stocked in depth across the standard size range, so a buyer with an urgent doorway to fix can usually order without waiting on a production run — single units are ordered as easily as larger quantities. Stock levels do vary by size and grade; check plastock.co.uk for current availability at the time of order. Actual delivery timing depends on courier network and location — check the site for the current estimate.

13.2 Roll Stock

Roll stock is the route to polar grade, ribbed grade, fire-retardant and coloured strip — none of which are currently offered in kit format. It is also the right choice for non-standard doorway sizes, for buyers maintaining large estates who prefer to hold bulk stock on site for rapid strip replacement, and for buyers who want to specify their own rail and fixing arrangement rather than using the standard kit hardware. Rail and plate stock is held separately in the same widths as the kit range, so a complete installation can still be assembled from components even where a ready-made kit is not available. Roll pricing is competitive for trade and bulk buyers ordering multiple rolls at a time — contact the Plastock team for volume pricing.

From a 50m roll, a buyer can cut strips to exact length on site using a straight-edge and a sharp knife or guillotine. The PVC cuts cleanly and squarely without specialist tooling. One 50m roll of 300mm × 3mm strip provides enough material for multiple standard doorway installations, depending on doorway height and overlap specification.

13.3 Ordering

Thermastock can be ordered online, alongside every other material in the Plastock range, or directly through the Plastock team. There is no separate Thermastock account or checkout to navigate: strip curtain, rail and plate stock sits within the same product catalogue as acrylic sheet, polycarbonate, foam and everything else Plastock stocks. For buyers who already hold a Plastock account, Thermastock products can simply be added to an existing order. This is the practical expression of the combined-sourcing advantage — one website, one basket, one delivery, one invoice.

14. Specification Checklist

Use this checklist before placing any Thermastock order. The five minutes spent working through it will prevent the specification errors that account for almost every strip curtain complaint.

Step 1 — Measure the opening: Clear opening width and height (not the frame). Write both down before proceeding.

Step 2 — Define the traffic type: Pedestrian only → 200mm. Light vehicles and pedestrians → 200mm or 300mm. Forklifts and pallet trucks → 300mm or 400mm. Heavy forklift, high frequency → 400mm ribbed.

Step 3 — Define the temperature environment: Ambient (above 0°C) → standard clear crystal. Cold room (+2°C to 0°C boundary) → polar grade. Freezer (below 0°C) → polar grade. Below −20°C → confirm grade minimum temperature with Plastock.

Step 4 — Check compliance requirements: Food-contact (direct contact with exposed product) → food-contact grade available via Plastock's wider supply network, on application. Food environment (proximity, not contact) → standard Thermastock clear crystal suitable. Fire requirement → check venue/building regulations; confirm FR grade rating before specifying. REACH documentation required → confirm availability with Plastock.

Step 5 — Calculate strip count: Number of strips = (opening width ÷ strip width) × 1.5, rounded up. Do not skip the ×1.5 multiplier. Then: roll length needed = strip count × door height, plus 10% for trimming allowance.

Step 6 — Select supply format: Standard doorway, clear crystal grade → select the matching Thermastock ready-made kit. Polar or ribbed grade required, or non-standard opening → order roll stock plus rail and plates as separate components.

Step 7 — Specify the suspension system: Thermastock uses one rail-and-plate suspension system across the range — stainless steel rail with riveted stainless steel plates. For cold rooms and wash-down environments: confirm stainless grade 304 or 316 rail.

Common mistake — final reminder: Measuring the doorway width and dividing by strip width without applying the ×1.5 overlap multiplier. A curtain ordered this way will have gaps between strips and will provide almost no thermal or hygienic barrier.

15. Summary

Thermastock is Plastock's clear flexible PVC curtain strip — a practical, unglamorous product that most commercial and industrial premises need and few actively plan for until something goes wrong. Specified correctly, installed correctly and maintained as described in this guide, it does its job with little further attention: keeping heat or cold in, keeping pests and draughts out, and giving people and vehicles a safer way to pass through a busy doorway.

This article covers everything a buyer, specifier or facilities manager needs to make informed decisions: which grade for which environment, how to size strips correctly, what the compliance landscape looks like, where Thermastock sits honestly in a competitive market, and what to do when a curtain underperforms. Three things to remember above all others:

● Grade determines performance. Standard grade in a freezer is the wrong grade. Polar grade in a standard warehouse is unnecessary cost. Match the grade to the temperature environment and the problem does not arise.

● Overlap determines insulation. A curtain with strips spaced too far apart is not a barrier — it is a draught gap with strip curtains hanging in it. Apply the ×1.5 multiplier to the strip count calculation without fail.

● Compliance documentation matters. In food, pharmaceutical and regulated public-venue environments, a material without supporting paperwork is not specifiable regardless of its technical performance. Thermastock's REACH Declaration of Conformity is available on request. The FR grade has been independently tested by SGS (report ref. AJFTS26005894R01_EN, July 2026) to BS 2782-0:2011 Method 508A and is classified TP(b) under Approved Document B (Fire Safety), Building Regulations 2019 edition as amended 2020/2022/2025. EN13501 certification is still in progress — check plastock.co.uk for current status.

Thermastock is supplied from UK stock by Plastock, with same-day despatch on stocked items. For buyers who already work with Plastock for sheet materials, it adds strip curtain to an existing account without a new supplier relationship. For buyers new to Plastock, it is a straightforward product from a technical team with genuine materials expertise — available now at plastock.co.uk.

Request samples, get a quote, or speak to the team:
01494 449 975 • sales@plastock.co.uk