In a single phone call a procurement manager at a mid-sized refinery recently asked us the same question in three different forms: Which fabric offers better protection? Which endures daily use? And which won’t exceed the budget when placing an order for 500 units. The question of whether to choose a modacrylic IFR coverall or aramid arises in almost every refinery RFQ that we receive, and most of the suppliers respond with a shrug or a sales pitch rather than providing actual figures.
The guide explains what modacrylic and aramid fibers actually do within a flame-resistant fabric, in which one fiber is superior in certain situations, when combinations are more appropriate than using either fiber on its own, and how you should select the fiber to match your refinery’s particular hazard profile rather than making an arbitrary choice.
What Makes a Coverall “IFR”
IFR means that the material is inherently flame resistant; the flame resistance is inherent in the fiber and is not applied to the fabric by spraying or chemical treatment afterward. This one difference is something that many buyers do not realize, since it is the reason why IFR fabric does not lose its protective properties when subjected to repeated industrial washing, unlike treated FR fabric.
The protection provided by a modacrylic IFR coverall comes about because of the chemical structure of the modacrylic fiber, while that of an aramid IFR coverall is due to the molecular structure of the aramid fiber. In neither case is a topical treatment required, and the protection does not wash out. The difference between them lies in the way each fiber behaves when it is actually subjected to heat or flame, and it is this difference that determines which type is suitable for your operation.
Armstrong Products has been making IFR and FR coveralls at its facility in Boisar, Maharashtra, since 2009 and supplies them to refiners, petrochemical companies, and utility customers all over India, in the Gulf region, and to export markets. The product recommendations set out in this guide are based on the actual products used every day on the production floor, not on marketing material.
How Modacrylic Fiber Resists Flame
Modacrylic is a synthetic fiber that is acrylic that has been modified by having flame-retardant chemistry incorporated directly into the polymer. Unlike aramid, when it is exposed to heat, modacrylic releases a flame-suppressing gas at the point of contact, and this helps to prevent the flame from spreading over the fabric surface.
Modacrylic fabric thus has a real advantage in cases involving flash fire, that is to say, in situations with a sudden and short-lasting flame exposure, which is typical of incidents at refineries. It is also more natural in terms of softness and lighter in weight than aramid, which is why blends based on it usually consisting of about 50% modacrylic together with cotton and a smaller amount of aramid to provide structural strength are widely used for full-shift wear in hot climates. Moreover, it can be dyed easily, even to high-visibility yellow and orange, whereas pure aramid fiber cannot do so without having to undergo special treatment.
The disadvantage is that modacrylic fiber has a lower melting point and a greater tendency to shrink than aramid; it can shrink while aramid would not, which is the reason why pure modacrylic fabric is almost never used by itself in situations involving prolonged exposure to high temperatures.
How Aramid Fiber Resists Flame
Aramid fiber, whether meta-aramid or para-aramid, resists flame due to its inherent thermal stability and not because of the release of gas; the fiber neither melts nor drips and retains its shape at temperatures that are much higher than those that modacrylic can withstand. That is the reason why aramid is still the fiber preferred for use in situations involving sustained arc flash exposure, tasks adjacent to welding, and any job where heat exposure may last longer than a few seconds.
A typical blend of meta-aramid used in IFR coveralls consists of 93% meta-aramid, 5% para-aramid, and 2% antistatic fiber, since this ratio is found in most refinery-grade coveralls and is capable of balancing thermal stability with sufficient tensile strength to endure daily use.
In this case the trade-off is reversed. Aramid fiber is stiffer and less breathable than modacrylic, costs more per meter to produce, and retains more heat within the garment than a modacrylic mixture does. When workers are on shift for 10 to 12 hours in high ambient heat, this difference in comfort turns into a real compliance issue since those who feel too hot in their coveralls are much more likely to loosen their cuffs, omit layers, or find ways around the protection altogether.
Modacrylic vs Aramid Coverall: Full Comparison
| Factor | Modacrylic IFR Coverall | Aramid IFR Coverall |
| Flame resistance mechanism | Releases flame-suppressing gas on contact with heat | High thermal stability, doesn’t melt or drip |
| Best suited for | Flash fire risk, moderate heat, full-shift comfort | Sustained arc exposure, high-heat sustained roles |
| Comfort and breathability | Softer, lighter, better airflow | Stiffer, less breathable, retains more body heat |
| Typical blend ratio | ~50% modacrylic with cotton and antistatic fiber | ~93% meta-aramid, 5% para-aramid, 2% antistatic |
| Dye flexibility | Dyes easily, including hi-vis colors | Limited dye range without added treatment |
| Cost per garment | Lower fiber cost, more budget-friendly at volume | Higher fiber cost, reflects raw material and processing |
| Durability under heat | Shrinks at lower temperature thresholds | Holds structure at higher sustained temperatures |
| Common certifications | NFPA 2112, EN ISO 11612 (blend dependent) | NFPA 2112, EN ISO 11612, ASTM F1959 (arc-rated blends) |
No fabric comes out as the clear winner; when a refinery buyer is deciding between them, they are in fact making a choice between two different approaches to risk – namely, short-term flash exposure and sustained heat – and the straightforward answer for the majority of operations is that both are needed, not just one in place of the other.
Why Most Refinery Coveralls Blend Both Fibers
The section that most supplier catalogues omit refers to the fact that pure modacrylic and pure aramid coveralls are both available, but in most cases refinery-grade IFR coveralls actually combine the two fibers since each fiber compensates for the other’s weakness. When aramid fiber is incorporated into a modacrylic-cotton blend, it increases the fabric’s structural strength and raises the arc thermal protection value (ATPV) above the level that modacrylic by itself would provide. On the other hand, when modacrylic is included in a blend that is heavy in aramid, the hand feel becomes softer, and air circulation is improved without a significant loss of thermal ceiling.
Fabric engineers carry out direct tests using ASTM F1959, a standard that determines a material’s arc thermal protection value. It has been found that combining modacrylic and aramid fibers results in a higher ATPV than using either fiber on its own, which is precisely the reason why the 93/5/2 and 50/38/10/2 mix ratios you will see on the specification sheets are there in the first place; they are not arbitrary since someone has tested a number of different ratios and settled on those that perform well.
When a supplier says it’s as simple as “modacrylic or aramid, pick one,” that is generally an indication that they are selling from a limited range of fabrics rather than selecting the appropriate fabric for your specific hazard.
Matching Fabric to Your Refinery’s Risk Profile
Begin with the actual exposure that your crew will experience, not the fabric name listed on the specification sheet.
Flash fire risk in process areas (tank farms, loading racks, pipeline work):
In process areas (such as tank farms, loading racks, and pipeline work), there is a risk of flash fire; a blend that is forward in modacrylic provides sufficient protection together with much better all-day comfort, a factor since crews are outdoors in the Gulf heat for 10 hours or more.
Sustained arc flash risk (electrical switchgear, substations, MCC rooms):
When it comes to electrical switchgear, substations, and MCC rooms, there should be a lean approach towards aramid. Here, sustained thermal stability is more important than comfort, and arc-rated blends that have a higher aramid content will have a higher ATPV.
Mixed-hazard turnaround and shutdown work:
The kind of work involved in turning a plant around or shutting it down is when the blended fabric proves its value. A blend made up of 50% modacrylic, 38% cotton, 10% aramid, and 2% antistatic material provides protection against flash fire and includes enough aramid to withstand short periods of arc exposure without having the heavy and stiff character of a garment that is heavy in aramid.
Chemical splash combined with flame risk:
The risk from a chemical splash together with fire means that the choice of fabric is of less importance than having a chemical-resistant layer or wearing a garment that is rated for dual hazards, no matter what fiber is underneath.
Cost Per Unit: What Actually Drives the Price Gap
Aramid fiber is more expensive to produce than modacrylic at the raw material stage, and this difference is also reflected in the final garment. When placing a large order with a refinery, buyers generally observe a significant per-unit premium for aramid-heavy coveralls as compared to modacrylic-based blends that have the same weight and certification level.
Even so, the cost per item is not equivalent to the cost per year of protection. Because aramid fiber has a greater heat resistance and structural durability, it usually results in a longer service life when subjected to heavy industrial washing, thus reducing the total cost difference over a two- to three-year period during which the item is replaced. A blend that is oriented towards modacrylic and that shrinks or thins out after 18 months of daily washes can end up costing more in replacements than the initial savings that it appears to offer.
Before making a bulk purchase solely on the basis of price, ask the supplier for information regarding the wash-cycle durability.
Buying Checklist for Refinery Procurement Teams
- Confirm the exact fiber blend ratio, not just “modacrylic” or “aramid” as a category
- Match the blend to your dominant hazard: flash fire, sustained arc, or mixed exposure
- Request ATPV or cal/cm² rating if arc exposure is a factor, tested under ASTM F1959
- Check certification against NFPA 2112 or EN ISO 11612 depending on your export or operating region
- Ask for wash-cycle durability data, not just day-one fabric weight and feel
- Confirm GSM (fabric weight) suits your climate: lighter GSM for extended outdoor shifts and heavier for cold-weather or layered use
- Verify antistatic fiber content is included if your site has static discharge risk
- Request a sample garment for a full-shift wear trial before committing to bulk quantities
- Confirm the manufacturer can supply consistent blend ratios across repeat orders; batch-to-batch fabric variance is a real sourcing risk
Common Mistakes Buyers Make
Selecting a fabric on the basis of price alone is inadequate. The cheapest modacrylic blend listed on the quotation sheet might not meet the ATPV rating that your site’s hazard assessment really calls for. Choosing price without a corresponding certification isn’t a valid comparison; it is merely a guess.
If “IFR” is all the information you need, then it only shows fiber’s stance on the flame resistance of the fiber itself; it gives no indication as to whether that particular blend is suitable against flash fire, arc exposure, or both. Two IFR coveralls can therefore differ greatly in performance depending on their fiber ratio.
Comfort should not be regarded as a factor that affects compliance. If coveralls are too hot or too stiff, workers will make changes on the job such as rolling up the sleeves, leaving the zippers open, and omitting layers. This quietly undermines the protection for which you paid. In this case, comfort is not a minor issue; it is involved in whether or not the clothing is worn properly.
Omitting the wear trial is how procurement teams end up with a warehouse full of coveralls that no one wants to wear because they based their order of 500 units on a specification sheet without first carrying out a field trial with their own crew in their own climate and under their own shift length.
Maintenance and Garment Life
Even if the fabric is made from IFR material such as modacrylic or aramid and does not lose its flame resistance as treated flame-retardant fabric can when washed, this does not mean that the garment requires no maintenance at all. Washing the garment at temperatures that are too high during industrial laundering can still cause a gradual deterioration of the fabric structure, especially in blends that are higher in modacrylic and have lower shrinkage thresholds. You should use only the washing temperature specified by the manufacturer, avoid using bleach and fabric softeners (since softeners may coat the fiber and affect the flame performance on certain types of blends), and at each laundering should check the seams and the reflective tape rather than waiting until there is obvious wear.
When the coveralls are rotated so that no individual piece undergoes more washings each month than the fabric is rated to withstand, the overall lifespan of the fleet is extended more than by any other maintenance action.
Conclusion
The question of whether to choose modacrylic or aramid isn’t really concerned with which fiber is objectively superior, since it depends more on the kind of hazard your crew encounters most frequently and the number of hours each day that they will be wearing the garment. Modacrylic is justified on the grounds of comfort and its performance in the event of a flash fire, while aramid is justified because of its thermal stability when exposed to continuous heat. Most refineries end up having to use a mixture of both, with the proportions of the blend being designed to match their particular risk profile rather than selecting a single fiber from a specification sheet.
The Armstrong Products facility in Boisar, Maharashtra, produces both modacrylic-based and aramid-based IFR coverall blends, and the site has been constructed in accordance with NFPA 2112 and EN ISO 11612 specifications to meet the needs of buyers in the refinery, petrochemical, and industrial sectors in India, the Gulf region, and in export markets. If you would like advice on which blend ratio is suitable for your site’s particular hazard profile, contact our product team to arrange a sample and wear trial before you decide on purchasing in bulk quantities.
FAQs
What is the main difference between modacrylic and aramid IFR coveralls?
Modacrylic has the ability to resist flames since it gives off a flame-inhibiting gas when it is heated, which makes it more suitable for situations involving flash fire and provides better everyday comfort. Aramid resists fire due to its inherent thermal stability, maintaining its structure at higher temperatures when exposed to them, a property that makes it more appropriate for use in cases of arc flash and prolonged heat exposure. Most refinery-grade coveralls combine both fibers in order to provide protection against a broader range of hazards.
Which fabric is better for refinery flash fire protection?
Blends that have a high proportion of modacrylic generally do well in resisting flash fire due to the fiber’s gas-release feature and provide greater comfort during long periods spent outdoors. In the case of any site that has a combined arc flash hazard, it is worth paying the extra cost for a blend that contains a significant amount of aramid.
Do modacrylic coveralls cost less than aramid coveralls?
Since aramid fiber is more expensive to produce, this is usually reflected in a per-unit price premium for coveralls that contain a high proportion of aramid. The better heat resistance of aramid can extend the life of the garment when it is laundered heavily, which as a result can reduce the total cost over the course of the replacement cycle.
Can a modacrylic coverall meet NFPA 2112?
Yes, blends based on modacrylic can comply with NFPA 2112 provided that the particular fabric construction and weight are taken into account; certification is based on the test results of the finished fabric and not simply on the name of the fiber, so you should ask for the actual test certificate relating to the blend you are purchasing rather than just being given the statement that “modacrylic meets NFPA 2112.”
What blend ratio is most common in aramid IFR coveralls?
The composition usually consists of 93% meta-aramid, 5% para-aramid, and 2% antistatic fibre. This proportion achieves a balance between thermal stability and sufficient tensile strength for ordinary industrial use, and it is the one responsible for the formulation of most refinery-grade aramid coveralls available on the market.
Is a blended modacrylic-aramid fabric better than either fiber alone?
Yes, in most cases with regard to refinery operations. By blending, aramid is able to increase the fabric’s arc thermal protection value beyond what modacrylic on its own can achieve, while modacrylic ensures that the garment remains lighter and more breathable than one made from a fabric that is heavy in aramid. A typical example of this is a blend consisting of 50% modacrylic, 38% cotton, 10% aramid, and 2% antistatic material, which has been designed specifically to achieve this balance of advantages.
How do I know which fabric suits my site’s specific hazard?
Choose the fabric according to the type of exposure you have. In areas where there is a risk of flash fire, a blend that is rich in modacrylic is preferred since it provides comfort. When there is a risk of sustained arc flash in electrical areas, a blend that is rich in aramid is recommended because of its thermal stability. In the case of turnaround work involving mixed hazards, a balanced blend should be used rather than having one of the fibers at the extreme.
Does modacrylic fabric lose its flame resistance after washing?
Not because the flame resistance is due to the fiber itself rather than being the result of a surface treatment; even though the correct wash temperature and avoiding fabric softeners are important for the overall durability of the fabric, the flame-resistant property itself does not wear away over the lifetime of the garment.
Can modacrylic and aramid coveralls both be made in high-visibility colors?
Modacrylic can be dyed directly into high-visibility yellow and orange without the need for any extra treatment, which is one of the reasons why it is widely used for high-visibility flame-resistant workwear. In contrast, pure aramid fiber has a more restricted dye range and usually requires additional treatment in order to achieve the same level of high-visibility brightness.
What should I ask a supplier before placing a bulk refinery coverall order?
Request the precise fiber blend ratio, the ATPV or cal/cm² rating where there is arc exposure, the specific certification standard that the fabric complies with (either NFPA 2112 or EN ISO 11612), the wash-cycle durability data, and a sample garment so that a field wear trial can be carried out. If a supplier is unable to provide these answers directly supported by test documentation, then they represent a sourcing risk no matter what fabric they are quoting.