Durafoam™ DK Series is UL Recognized as a Component for Gasket and Seals category (JMLU2), Plastics flammability (QMFZ2), including (QMFZ8) Plastics Certified for Canada.
Built for Enclosure, Gasket, and Seal Applications
Monmouth Rubber states that its Durafoam™ DK Series is UL Recognized under JMLU2 MH10200 and that the line is recognized across all five hardnesses to UL 50E, UL 157, UL 508. Monmouth also describes the DK Series as the company’s only full line of ASTM SCE 41 through SCE 45 closed-cell rubber with that recognition profile.
For OEMs, converters, and gasket fabricators, that gives one material family with multiple hardness options for applications that need consistent closed-cell gasket performance and documented third-party recognition.
What UL 157 Covers
Monmouth explains that UL 157 applies to gaskets and seals and ties to the UL category JMLU2, which it describes as the main category for elastomeric and composite gasket materials. According to Monmouth, that category includes forms such as O-rings, seals, shaft seals, flexible cellular gaskets, facings, sheet materials, special forms, and poured-in-place gaskets.
Monmouth further says that materials in this category are evaluated for key material-performance properties, including tensile strength, elongation, compression set, tensile set, hardness, low-temperature performance, and retention of properties after accelerated aging and environmental exposure. On its UL gasket materials document, Monmouth also lists tests associated with UL 157 such as accelerated air-oven aging, compression set, low-temperature, hardness, immersion, detergent/cleaner, and bursting strength testing.
Why UL 157 Matters
UL 157 matters because it addresses the gasket or sealing material itself, not just the finished equipment around it. Monmouth distinguishes JMLU2 as the generic category for gasket-and-seal material properties, while a separate listing such as JMST2 relates to a more specific application. That distinction helps engineers and buyers understand when a material has been recognized on the basis of gasket-related performance characteristics.
For enclosure and equipment designers, that can be important when selecting a closed-cell material for sealing against air, dust, moisture, vibration, or environmental exposure while also aligning with broader product safety and compliance needs. This point is supported by Monmouth’s own positioning of the DK Series as a UL-recognized closed-cell rubber sponge family spanning multiple hardness and density levels in one line.
Monmouth Rubber’s UL Recognized DK Series
Monmouth’s published DK Series literature states that all five hardnesses in the line are recognized to JMLU2 (UL 50E, UL 157, UL 508), and QMFZ2 (UL 94 HF-1), and are also Recognized to QMFZ8 to CAN/CSA C22.2 No. 0.17. The document identifies the grades as:
- DK1111
- DK2121
- DK3131
- DK4141
- DK5151
Monmouth’s technical sheets also show the series spanning approximate densities from 6 +/- 2 pcf through 13 +/- 4 pcf, giving specifiers a range of material options within the same recognized family.
One Closed-Cell Family Across ASTM SCE 41 Through SCE 45
Monmouth states that the Durafoam DK Series is its only full line of ASTM SCE 41 through SCE 45 closed-cell rubber recognized to JMLU2, QMFZ2 , and the noted Canadian listing QMFZ8. That makes the line useful for customers who want to stay within one material platform while moving across different compression levels or design targets.
Monmouth also says the DK Series is available in buns, sheets, rolls, and tape, which helps support both fabrication flexibility and repeatable sourcing for gasket production.
Related UL Standards in the DK Series
UL 50E
Monmouth lists the DK Series as evaluated to UL 50E, a standard commonly associated with enclosure considerations. Monmouth includes UL 50E alongside UL 157 and UL 508 in its DK Series product literature and marketing pages.
UL 508
Monmouth also lists the DK Series as evaluated to UL 508, further supporting use in applications where gasket materials are selected as part of a broader electrical or equipment compliance strategy.
UL 94 HF-1
The same Monmouth literature states that all five DK hardnesses have been evaluated to UL 94 HF-1, adding flame-related recognition to the material family’s profile.
UL 94 V0
The DK5151 has been successfully evaluated to UL 94 V0, which is a more severe standard for vertical flammability as opposed to horizontal flammability (HF-1), adding flame-related recognition to the DK5151 profile.
Third-Party Recognition and OSHA Context
OSHA explains that its Nationally Recognized Testing Laboratory (NRTL) Program recognizes private-sector organizations to perform product certification for certain products so they meet applicable safety requirements in OSHA’s electrical standards. OSHA also maintains a page for UL within that NRTL program.
That government context helps explain why UL recognition is meaningful in regulated product environments: it reflects certification activity performed by an OSHA-recognized testing laboratory within the NRTL framework.
Applications
Monmouth’s description of the JMLU2 gasket-and-seal category shows that recognized materials can be relevant to a wide range of product forms, including:
- Flexible cellular gaskets
- Sheet gasket materials
- O-rings and seals
- Shaft seals
- Special forms
- Poured-in-place gasket designs
Why Specify Monmouth Durafoam™ DK Series
- Recognized as Component by UL to JMLU2, QMFZ2 and QMFZ8 across all five hardnesses, this includes evaluation to UL 50E, UL 157, UL 508, and UL 94 standards.
- Positioned by Monmouth as the only full line it offers from ASTM SCE 41 through SCE 45 with that combination of recognitions.
- Available in multiple supply formats, including buns, sheets, rolls, and tape.
- Supported by Monmouth’s published technical-property sheets and UL gasket documentation.
Request Technical Information
If your application requires a closed-cell gasket material with documented recognition to UL 157 and related standards, Monmouth Rubber’s Durafoam™ DK Series offers a single family of materials spanning multiple hardness levels for gasket and seal design.
Samples and additional technical information are available by contacting John M. Bonforte, Sr. General Manager and Technical Director, Phone: 800-375-1960 Ext. 112, Email: John Sr.
