The devices of this SAE Standard provide the means by which passenger compartment dimensions can be obtained using a deflected seat rather than a free seat contour as a reference for defining seating space. All definitions and dimensions used in conjunction with this document are described in SAE J1100. These devices are intended only to apply to the driver side or center occupant seating spaces and are not to be construed as instruments which measure or indicate occupant capabilities or comfort. This document covers only one H-point machine installed on a seat during each test. Certified H-point templates and machines can be purchased from:
- SAE International
400 Commonwealth Drive
Warrendale, PA 15096-0001
Specific procedures are included in Appendix A for seat measurements in short- and long-coupled vehicles and in Appendix B for measurement of the driver seat cushion angle. Specifications and a calibration inspection procedure for the H-point machine are given in Appendix C. Additional considerations are necessary when a Head Restraint Measuring Device (HRMD) is mounted to an H-point machine (Appendix D).
The devices described in this document provide a method for a reliable layout and measurement of occupant seating compartments and/or seats. They are not to be construed as tools that measure or indicate occupant capabilities or comfort.
The devices are intended for applications at designated seating positions. They are not intended for use in defining or assessing temporary seating, such as folding jump seats.
When using the H-Point Machine (HPM), interactions can occur between adjacent seating positions (i.e., having an HPM installed at the center occupant position can change the results obtained for the outboard occupant position). Therefore, only one machine should be installed in a particular row of seats during each test.
This revision incorporates an inspection procedure for checking calibration of the H-point machine (Appendix C). It also adds specifications for the mounting surface of the head restraint measuring device. Other changes include:
- 10 year phase-out period for the HPM
- Revision of HPM weight specification from 167 to 169.6 lb to reflect current HPM build
- New ambient humidity specification
- Narrower range of ambient test temperatures
- Clarification of muslin cloth specification
- Extensive revision of short couple method and addition of long couple method to Appendix A
- Terminology consistent with SAE J1100
- Editorial clarifications
SAE J4002 (HPM-II) and SAE J826® (HPM) shall co-exist for a transition period of at least 10 years, preferably no longer, from the first publication date of SAE J4002 (August 2005). Following this transition period SAE J826® will be withdrawn. During the transition period, it remains up to the vehicle designers to decide which HPM to use. Regulatory bodies and other parties that need to know shall be informed regarding which HPM was used.