ArcWear™ Sentinel™ 4500 Series Protective Outerwear Technical

Sentinel LogoThe Sentinel™ 4500 Series, comprising an FR Polyurethane moisture/chemical barrier outer shell and a 100% FR Cotton Knit inside, excels in joining comfort with durability and protection. While keeping workers safe from electric arc and flash fire, the durable Sentinel™ material extends the usable life and level of comfort well beyond other rainwear.

Sentinel™ is a waterproof and windproof outerwear product that combines high visibility worker conspicuity with protection from industrial thermal hazards associated with electric arc and hydrocarbon flash fire. Sentinel is best suited for use by electric and gas utilities as well as the oil and gas industry and offers NFPA 70E PPE CAT 2 protection.

Sentinel™ is ASTM, NFPA 70E, NFPA 2112 and ANSI certified: Electric Arc (ASTM F1891, NFPA 70E PPE CAT 2), Flash Fire (ASTM F2733, NFPA 2112), Chemical Penetration (ASTM F903) and High Visibility (ANSI 107 Class 3 Level 2). 

Property Summary

FR Polyurethane Outer Shell

Polyurethane (PUR and PU) is a unique material that offers the elasticity of rubber combined with the toughness and durability of metal. Polyurethane is a polymer composed of a chain of organic units joined by carbamate (urethane) links. While most polyurethanes are thermosetting polymers that do not melt when heated, thermoplastic polyurethanes are also available. Thermoplastic polyurethane (TPU) is any of a class of polyurethane plastics with many useful properties, including elasticity, transparency and resistance to oil, grease and abrasion. Technically, they are thermoplastic elastomers consisting of linear segmented block copolymers composed of hard and soft segments.

Polyurethanes are used in the manufacture of flexible, high-resilience foam seating; rigid foam insulation panels; microcellular foam seals and gaskets; durable elastomeric wheels and tyres (such as roller coaster wheels); automotive suspension bushings; electrical potting compounds; high performance adhesives; surface coatings and surface sealants; synthetic fibres (for example, Spandex/Lycra); carpet underlay; hard-plastic parts (for example, electronic instruments) and hoses.

Polyurethane Laminate (PUL) is a compound fabric made by laminating a cloth fabric to a thin film of polyurethane. Polyurethane laminated fabrics have a wide range of applications in medical, automotive and industrial garment use. Most PUL fabric is made by laminating lightweight polyester interlock knit fabric to a one millimeter thick film of polyurethane. There are two processes used for lamination: solvent lamination, which fuses the fabric and polyurethane film into a single monolithic fabric and hot melt, which uses heat activated glue to adhere the fabrics together.

Electric Arc

For electric utility workers and others that work around energised electrical lines or plant, the hazard of momentary electric arc flash is real and extremely dangerous. Over the past 11 years, according to a BLS Census of Fatal Injuries report, nearly 2,400 lives were lost by this hazard. In addition to the electrocution aspect, this number includes lives lost as a result of the burn injury sustained in the arc flash.

It is this burn injury that protective clothing is intended to reduce. With temperatures as high as 4000° C (7232° F), an electric arc flash can be extremely destructive. Protective clothing should be utilised in such a way as to reduce the potential burn injury, limiting the amount of the body that would sustain a second-degree burn injury.

In the event of an electric arc flash, protection is measured by the ability of a fabric to keep second-degree burn injury to a minimum. An arc rated product will not further the extent of an injury, nor will it melt, drip or ignite. In comparing arc rated products, higher arc ratings (ATPV) are more protective.

Flash Fire

In a flash fire, a matter of seconds can mean the difference between minor burns and life-threatening injuries. By far the greatest factor affecting survivability is the percentage of the body that receives second and third-degree burns; the lower the level of total body burn, the greater the chance of survival. Flame resistant Sentinel™ helps protect the wearer from the heat and flame of a flash fire, providing valuable seconds for escape and minimising the potential for burn injury.

The thermal protective properties of fabric systems can be demonstrated through the use of the Thermal Protective Performance (TPP) Test, as described in NFPA Standard 1971 and ASTM D4108. The Thermal Protective Performance Test measures how well a fabric system can protect the wearer against second-degree burns in a flash fire. The higher the TPP value, the more thermal protection the fabric provides relative to other fabrics. 

A flash fire rated product minimises the predicted burn injury from an engulfing hydrocarbon flash fire. Both textile and garment design play a role in protection. Here, protection is measured by minimising the percentage of overall body burn, with an emphasis on limiting second and third-degree burns.

High Visibility

In foul weather and low light conditions, work zones that put workers in close proximity to oncoming traffic create a tremendous work hazard. To protect the worker, you must maximise a driver's reaction time. The worker needs to be visible to the oncoming traffic even when the job at hand diverts the worker's attention away from the oncoming traffic. High visibility work wear is necessary to create contrast between the worker and the work zone.

The ANSI 107 standard establishes a set of performance criteria for high visibility apparel. The standard defines three garment categories that are based on worker hazards and tasks, complexity of the work environment or background and vehicular traffic and speed.

Sentinel™ garments in Fluorescent Lime Yellow or Fluorescent Orange provide excellent worker day/night high visibility and both fabrics comply with ANSI 107 Class 3 Level 2.

Chemical Penetration Resistance (including Steam and Hot Water)

Workers who work around chemicals (including steam and hot water) know how dangerous they can be and how important it is to be protected at an appropriate level as indicated by MSDS sheets. Chemical burns are not only expensive to recover from, but they can also be deadly. It is the purpose of splash protective apparel to reduce hazardous chemical exposure to direct skin.

There are two different ways to determine the protective ability of a material from which splash protective apparel is made: penetration resistance and permeation resistance testing. Sentinel™ chemical splash resistant garments offer protection from chemical penetration, which is significantly different from chemical permeation.

Penetration Resistance

Penetration resistance testing evaluates if liquids physically penetrate materials using visual observation for detection. It is intended for use with liquid-splash, liquid-tight, EPA level B or C garments. The primary purpose is to keep liquids from contacting the wearer’s skin.

Permeation Resistance

Permeation resistance testing measures the passage of chemicals (liquids and gases) through a material at a molecular level and requires sensitive analytical equipment to detect chemical breakthrough. It is intended for use with vapour-protective, gas-tight, EPA level A garments. The primary purpose is to isolate the wearer from a surrounding hazardous chemical environment.

ASTM F903 Test Method

Standard Test Method for Resistance of Materials Used in Protective Clothing to Penetration by Liquids

This test method is used to test specimens of protective clothing and candidate materials and constructions to be used in protective clothing. The resistance to visible penetration of the test liquid is determined with the liquid in continuous contact with the normally outside surface of the test specimen.

Test Criteria;

ArcWear™ Sentinel™ is resistant to oils, hydrocarbons, salts, alkalies and most alcohols.

How Sentinel™ Protects


DuPont Nomex

DuPont’s Nomex® wants you to feel that your clothing is there for you when you need it, so you can perform to your fullest potential when facing intense heat and flames. Nomex® thermal technology has a 40-year history demonstrating proven protection against electric arc flash and flash fire. Inherently flame resistant Nomex® is valued by military personnel, those employed by the chemical and petrochemical industries, electrical utility workers and firefighters because it protects them from thermal hazards associated with electric arc flash and flash fire. Nomex® is also worn by F1®, NASCAR® and MotoGP™ drivers, riders and pit crew who, for decades, have relied on racing apparel made with DuPont™ Nomex® brand fibre to help keep them safe from harm. Only one brand provides this level of protection and that brand is Nomex®.

3M Scotchlite

3M™ Scotchlite™ reflective material makes people visible – it reflects light back to its source such as vehicle headlights, making the garment wearer visible to the motorist more easily and earlier. As a result, motorists have more time to react.

Sentinel™ Care Instructions

ArcWear™ Sentinel™ Extended Care – hang garment after each use and keep clean for optimum performance. For maximum performance it is recommended that Sentinel™ be laundered after exposure to any liquid other than water.

End User Intended Use

ArcWear™ Sentinel™ meets the requirements of ASTM F1891 “Standard Specification for Arc and Flame Resistant Rainwear” and ASTM F2723 “Standard Specification for Flame Resistant Rainwear for Protection Against Flame Hazards”. End users must use this product ONLY for protection against inclement weather, electric arc exposures and flash fire exposures. Sentinel™ also provides chemical penetration resistance to several chemicals tested by the manufacturer in accordance with ASTM F903 "Standard Test Method for Resistance of Materials Used in Protective Clothing to Penetration by Liquids". For a complete list of chemicals tested, please email ArcFlashWear at This email address is being protected from spambots. You need JavaScript enabled to view it.