For industries that require materials on a large scale, consistency and quality are two of the most important considerations when thousands or even millions of products are being impacted by a material batch. This is important not only for one order, but as more and more orders are placed over time, each set of materials is expected to perform to the same specifications as the previous ones, as well as the ones that will follow. To ensure the uniformity of materials in settings where such consistency is important, industry standards have been established as a way to blend the quality control and categorization of materials.
There are many different kinds of standards in place, depending on business location and what services and materials are being used or manufactured. As one of the largest and most demanding organizations in the world, the United States Department of Defense has their own set of standards for the materials they require, which specify the numerous requirements products must meet to fill a role in their highly regimented system. MIL-PRF-26514 is one such requirement listing that pertains to rigid or flexible polyurethane foam for product packing materials.
While often referred to generically as standards, there are different variances in these regulation types that cover certain requirements of a product. There are standards, which the regulations are often generically lumped together as, as well as specifications, performance specifications and more. MIL-PRF-26514 is a foam performance specification, which details the functional performance requirements and guidelines for the material or product desired, as opposed to engineering or technical requirements which other regulation types cover.
While they are all very detailed documents, since the importance of materials and the quantity being ordered is great, they can help even a casual reader understand the characteristics of a product, by the standard’s applied requirements.
In the case of MIL-PRF-26514, polyurethane foam sheet materials, the majority of which are also known as open-cell foam, are the topic at hand. There are two types of materials included in this performance specification; Type I foam, which is standard polyurethane foam, and Type III, which is anti-static foam. A Type II classification did exist, but recent revisions have eliminated this variety of classification, and for the sake of reference consistency, Types I and III remained as they were.
After Type is specified, there are two Classes under each variety. This tiered breakdown is common in standards, regardless of the industry, because it provides black or white, yes or no answers to product questions. Class 1 materials are rigid polyurethane foams which can be thought of as non-resilient materials. An example is flower foam, which holds its shape but will compress and cave to pressure and maintain the imprint left in it after the release of pressure. Class 2 materials are flexible polyurethane, which are the traditional foam materials you think of being used in couch cushions that compress for comfort, but return to shape after the release of pressure. The performance standard also includes stipulations for the classification categories. For example, Class 2 materials have a limitation on the amount of compression creep that can occur in the material.
The final stipulation in MIL-PRF-26514 is Grade. These are broken into color segments, depending on the Type of material selected. Type I standard foam’s Class A material is blue, Class B green and Class C is standard charcoal foam. For Type III anti-static foam, Class A material is yellow, Class B red and Class C brown.
Having this sort of regimented structure makes the purchase process easier for both the buyer and the seller of foam packaging by reducing margin for error. A material simply does or does not qualify for a type, class or grade. This not only keeps materials that don’t meet specification from intentionally being sold, it also prevents the accidental sale of a material that isn’t a certain specification, saving both parties the time, trouble and money. Coding also allows easier storage and inventory, as it’s easy to classify stock according to the standard as well. If someone requests Type I, Class 2, Grade C Material, you can know exactly what they mean (standard, flexible, charcoal polyurethane foam) and where to find it, taking potential confusion out of the transaction.
This article is a summary of an in-depth military performance specification, intended only to give readers a general overview of a highly-detailed document. It does not cover every aspect of the specification and should not be treated as such. There are many performance and engineering requirements within the standard that must also be met before a material is fully compliant.
Type I – Standard
Type II – N/A
Type III – Anti-Static
Class 1 – Rigid
Class 2 – Flexible
(Type I) Grade A – Blue
(Type I) Grade B – Green
(Type I) Grade C – Charcoal
(Type III) Grade A – Yellow
(Type III) Grade B – Red
(Type III) Grade C – Brown
Stress curves may also be a factor in Grades.