sfi HARN01S003 Seat Belt for Upright Seating Installation Guide
- June 9, 2024
- sfi
Table of Contents
sfi HARN01S003 Seat Belt for Upright Seating
IMPORTANT NOTICE
The purpose of this guide is to provide motorsports vehicle drivers, owners
and mechanics with additional information on seatbelt installation. This guide
is for informational purposes only and in no way shouldit be construed to be
an express or implied warranty of safety or guarantee that Driver Restraint
Systems mounted in accordance with this guide will prevent any injury, systems
failure, property damage, or death. Participation in motorsports carries with
it the risk of serious injury, property damage and death at all times
regardless of which driver restraint systems are used. This informational
guide does not supersede or replace product manufacturer’s installation
instructions or sanctioning body rules and requirements. This guide applies to
Driver Restraint Assemblies which pertain to the SFI Specification 16.1 and
SFI Specification 16.5 compliance programs. Prior to any seatbelt installation
or installation modification, consult with the motorsports vehicle builder,
seatbelt manufacturer, and sanctioning body. At all times the driver and
vehicle owner have prime responsibility for the sate installation and use of
seatbelts.
SHOULDER BELTS
- Shoulder Belt Angle: 0 to -20° (-10° optimum) from horizontal
- Clear passage of webbing from top of shoulder (or head and neck restraint) back to the harness bar or mounting point without any interference of the seat openings
- Belts should be as short as possible back to the mounting points
Double Shoul der Belt (Over/Under Belt)
- Upper belt (2″ belt) 0 to -10° (-10° optimum)
- Body belt (3″ belt) -10 to -30° (-20° optimum)
- Separation between upper and lower belt 1′” to 2″
- Upper belt mounted to line up with the inside edge (closer to the neck) of the Body belt
Proper Wrap of Shoulder Belt:
LAP BELTS
Lap Belt Angle: -45 to -80° from horizontal
- Belt should ride within the curvature of the pelvic bone preferably just below the iliac crest
- There should be clear passage through the seat opening without webbing being corded or binding on edges of seat openings with a direct path to the mounting point
- The webbing should not ride against any hardware such as seat mounting brackets, bolts, or tabs
- Lap belt adjusters should be clear of the seat openings. Pull-up adjusters if outside the seat opening should be a minimum of2″ below the opening when the lap belt is tightened
- Belts to the mounting point should be as short as possible mounted beside the seat and never behind the seat
- Lap belt should be allowed to pivot freely at the mounting point
- Webbing should be allowed to pull on hardware in plane (straight) Position of the Cam Lock or Latch and Link
- Centered on the body IMo 2 inches below the belly button when all belts are tightened
CROTCH BELT- 6-POINT
Sports Car “Shell Type Seat” and aluminum seats with single crotch belt hole forward of the inside seat back from 10 to 12 inches: ( NOTE: Seats with a single hole positioned more than 12 inches from the inside seat back are designed for 5 point belt installations and may not be as efective for 6-point installations):
- Crotch Belt Angle: -20° (2″ rearward) through the hole
- Two separate anchors 4 to 6 inches apart (X
Containment Seats with Crotch belt mounting directly to seat bottom OR through holes provided at the back of the seat bottom: (Driver is sitting on the Crotch belts)
-
Crotch Belt Angle: -10° to-20° from the perpendicular just in front of the crotch with anchors 4 to 6 inches apart (C
OR -
Crotch Belt Angle Horizontal rearward to under the butt or to the back of the seat ( Option (typically for single-seat wide cockpits)
Crotch Belt mounting to the front side of the outboard ap anchors.(Option not illustrated) Considerations:
- Routing of crotch belts should have a clear and unobstructed path to the mounting point
CROTCH BELT-5-POINT
Sports Car “Shell Type Seat” and aluminum seats with single crotch belt hole forward of the inside seat back from 11 to 13 inches:
- Crotch Belt Angle: Chest line to 20° through the hole
- Crotch Belt should never wrap around the front of the seat – there should be a pass through
- Crotch Belt is used only to maintain position of the lap belt
NEGATIVE G BELT-(7H POINT)
Negative G Strap Angle: 20° to 25° (Chest line extension on a 25°seat back angle)
- Used in conjunction with a 6-point crotch belt system as an additional point to maintain the position of the lap belt in “Negative G” ie. rollovers
SFI Foundation, Inc.
15708 Pomerado Road, Suite N208, Poway, CA 92064 (858)451-8868 FAX#
(858)451-9268
- website: www.sfifoundation.com
- email: sfi@sfifoundation.comn