How does the HPMK-I differ from the standard HPMK?
The HPMK-I adds two significant upgrades: the HRS-I outer shell with integrated Climashield® insulation (5-ply vs 4-ply) provides higher passive thermal retention, and the heat source is upgraded from a standard self-heating liner to a more powerful 4-Cell Ready Heat blanket. The packaged size is slightly larger (H 8 × W 11 × D 6 in, 4 lb 14 oz vs 6.75 × 10.5 × 5.5 in, 3 lb 8 oz), reflecting the additional insulation. The HPMK-I is the correct choice for cold-weather operations; the standard HPMK is sufficient for temperate environments.
Is the HPMK-I CoTCCC-recommended?
The HPMK-I is built directly upon the foundation of the CoTCCC-recommended HPMK, and NAR specifically states it meets new CoTCCC guidelines for hypothermia prevention. It delivers the same CoTCCC-compliant thermal protection as the standard HPMK with enhanced cold-weather performance. The CoTCCC recommendation for hypothermia prevention during casualty care applies to the HPMK system family, of which the HPMK-I is the insulated variant.
How does the 4-Cell Ready Heat blanket differ from the standard HPMK liner?
The 4-Cell Ready Heat blanket provides four separate heating cells distributed across the patient's body for even heat delivery, compared to the standard HPMK's single-cell shell liner. Both are oxygen-activated and provide up to 10 hours of continuous dry heat. The 4-cell design is considered more effective for full-body warming because it distributes active heat generation across multiple body regions rather than concentrating it in one area, improving overall thermal management in the most severe hypothermia scenarios.
What environments specifically call for the HPMK-I over the standard HPMK?
The HPMK-I is most indicated for operations in alpine, arctic, sub-arctic, and cold-weather maritime environments where ambient temperatures are consistently below freezing and exposure times may be extended. It is also appropriate when anticipated casualty evacuation times are prolonged (multiple hours), when patients present with wet or immersion injuries, or when operations involve high altitude where temperature drop is significant. In temperate or warm environments, the standard HPMK provides appropriate performance at lower pack weight.
Does the HPMK-I require any tools or activation steps to deploy?
No. The entire HPMK-I system deploys through two steps: open the vacuum packaging using the NAR Red Tip Technology pull tabs (works with gloves), and expose the 4-Cell Ready Heat blanket to air. Heat generation begins immediately upon air exposure. No batteries, buttons, lighters, microwave, or hot water are required. This self-activation design ensures the kit is deployable in any field condition without dependence on additional equipment or power sources.
Is the HPMK-I CoTCCC-recommended?
Yes. The HPMK® (Hypothermia Prevention and Management Kit) is CoTCCC-recommended for hypothermia prevention during casualty care. The HPMK-I is the insulated variant of this CoTCCC-recommended system — providing the same recommendation compliance with enhanced thermal performance for cold-weather operations.
What is included in the HPMK-I?
The HPMK-I includes the HRS-I (Heat Reflective Shell — Insulated) outer shell with built-in Climashield insulation and the Ready Heat 4-cell oxygen-activated self-heating liner, which sustains 10 hours of continuous dry heat without external power. The complete kit is vacuum-packaged for minimal cube footprint with Red Tip Technology® for rapid deployment.
How long does the Ready Heat liner in the HPMK-I stay active?
The Ready Heat 4-cell self-heating liner sustains approximately 10 hours of continuous dry heat after activation — no external power source required. The liner activates on contact with oxygen when removed from the sealed packaging. Once activated, heat is sustained throughout the 10-hour window.
What temperature rating does the HPMK-I provide?
The HPMK-I's combined insulation and active warming system is designed to maintain normothermic body temperature in cold-weather field environments. Specific temperature performance data is published by North American Rescue based on testing in controlled cold environments. The insulated shell (Climashield) plus active warming liner provides significantly greater cold-weather performance than the standard HPMK's shell plus liner combination.
Can the HPMK-I be used in temperate environments?
Yes, but the standard HPMK is more appropriate for temperate operations. The HPMK-I's Climashield insulation adds weight and pack volume that provides no practical thermal benefit in warm or temperate conditions. Reserve the HPMK-I for cold-weather deployments and use the standard HPMK for general and temperate operations.
