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Standardized Testing to Delineate How Materials, Construction Impact Performance Characteristics of Support Surfaces to Enhance Objective Clinical Decision-making for PI Prevention

Kristen Thurman, PT, MPT, CWS, CFPS; David Driscoll, BS, AE


Clinicians are challenged with having objective data to choose support surfaces that will offer the most ideal clinical performance for patient populations. Support surfaces are designed with different materials and constructed in various ways to provide therapeutic value. Using laboratory Support Surface Standards testing can assist with understanding the performance characteristic differences between surfaces providing more objective data for clinicians to match performance characteristics to patients’ needs.


Support surfaces with various cover materials and construction were selected to test using the 2019 American National Standard for Support Surfaces Standardized tests for Immersion.¹ A foam mattress with a nylon cover, a foam-filled air cell surface with a polycarbonate cover, and a 10” air surface with a polycarbonate cover were selected. The Immersion Standardized Test, Section 6, was performed on each surface.

graphic showing effect of 95-pound weight on support surface
photo of 95-pound weight on support surface
S3I Hemispherical Indenter Test
ANSI/RESNA SS-1:2019, Vol. 1, Sec. 6: Envelopment and Immersion – Hemispherical Indenter Test


The immersion results were 26.4% for the foam/nylon cover, 30% for the foam-filled cells/polycarbonate cover, and 61% for the 10-inch air cells/ polycarbonate cover. The foam/nylon surface had the least amount of immersion, whereas the air/polycarbonate surface had the most immersion.

Cover FabricCell MaterialImmersion
(mm and %)
Nylon top cover
layered foam used in support surface
Polycarbonate top cover
Foam-filled air cells used in support surface
Foam-filled Air Cells
Polycarbonate top cover
10-inch air cells used in support surface
10″ Air Cells


The materials and construction of the support surfaces did influence the performance characteristic of immersion. Clinicians looking for surfaces with higher immersion, for example with immobile patient populations where more pressure redistribution is desired, may consider surfaces constructed with air cells and a polycarbonate cover over foam surfaces with a nylon cover. Patients who are working in rehabilitation may benefit from less immersion, therefore the foam surfaces may be a better choice. Every support surface, with a varying design and cover material, will have a different outcome, as evidenced by Call and Capunay. They reported that surfaces had varying results of immersion from 47.3% (a powered air surface) to 31.4% (a self-adjusting technology air surface).² Obtaining these standardized test results will give clinicians objective data in which to compare performance characteristics, such as immersion, of support surfaces.


Differences in support surface design and materials influence performance characteristics that can affect patient outcomes. Standardized testing allows for objective comparisons of support surface performance characteristics for clinicians to make evidenced-based choices for specific patient populations.

About the Authors

Kristen Thurman, PT, MPT, CWS, CFPS
Kristen is Senior Director of Solution Management for Agiliti. She is also chair of the Support Surface Standards Committee, a subcommittee of the National Pressure Injury Advisory Panel (NPIAP). Kristen is a member of the ISO Technical Committee 173, Working Group 11 — Assistive Products for Tissue.

David Driscoll, BS, AE
Dave is Director of Research and Development at Agiliti. He is a member of the Support Surface Standards Committee, a subcommittee of the National Pressure Injury Advisory Panel (NPIAP). Dave is a member of the ISO Technical Committee 173, Working Group 11 — Assistive Products for Tissue.

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Agiliti stands behind the authenticity of this data.
Poster Presentation at the Symposium on Advanced Wound Care (SAWC) Spring, Phoenix, Ariz., 2022.


  1. American National Standards Institute/Rehabilitation Engineering and Assistive Technology Society of North America. SS-1-2019 RESNA Standard for Support Surfaces— Volume 1: Requirements and Test Methods for Full Body Support Surfaces. Arlington, VA: Rehabilitation Engineering and Assistive Technology Society of North America; 2019.
  2. Call E, Capunay C. Standardized testing to evaluate the microclimate, immersion, and envelopment capabilities of a support surface. Accessed Dec. 17, 2021: