standard specification for football helmets

Why We Need a Standard?

4 April 2011 Tugas UAS Standarisasi Material 2

Football Helmet


History of Football Helmet

1896

Lafayette College halfback George "Rose" Barclay began to use straps and earpieces to protect his ears.

1920

The first time in the sport of football that the idea of protection and a helmet started to be used.

1939

The Riddell Company from Chicago, Illinois decided to start manufacturing plastic helmets because they felt this would be a safer material for football players to wear.


Standard Specification for Football

Helmet

Standard that been used:

ASTM F 717

Standard Specification for Football Helmets

ASTM F 429

Shock-Attenuation Characteristics of Protective

Headgear for Football

4 April 2011 5Tugas UAS Standarisasi Material

ASTM Testing Procedure

ASTM Standards are based upon the use of a

number of ASTM Methods to perform the

property measurement.

The methods provide very explicit direction with

respect to the equipment, the measurements, and

the data analysis.

Standardization of procedure and reproducibility

of results among laboratories is the goal of the

process.


Scope (ASTM F 717)

This specification covers new and reconditioned

football helmets intended for use in competitive play

and practice with particular reference to shock

attenuation requirements.

This specification establishes shock absorption

requirements of complete helmets when tested in

accordance with Test Method F 429 and establishes

requirements for construction, materials, visibility,

and labeling.


Materials and Manufacture

(ASTM F 717) Material that contact with head

shall not be of a type known to

cause irritation or disease.

The helmet, as tested, shall have

no rigid external projections

greater than 1⁄16 in. (1.6 mm) in

height, except for faceguard; chin

strap, nose bumper, or sweatband

hardware.

Any faceguards or faceguard

hardware installed on the helmet

must be removed prior to

testing.

All allowable external projections

shall be smooth and rounded so

as to minimize the potential of

injury.

Any internal rigid projections

that can contact the wearer’s

head during impact shall be

protected by some means of

cushioning or force spreading.

The helmet shall provide

peripheral vision clearance of at

least 105° to each side of the

median plane when the helmet is

adjusted to the reference head

form with the reference index.


Material for Football Helmet

Materials used for the

production of football helmets

have evolved from leather, to

harder leather, to molded

polycarbonate shells, which are

used today because of their

strength and weight.


Terminology (ASTM F 717)

Reference Index

The manufacturer’s recommended dimension

from the lowest point of the helmet face

opening to the basic plane of a reference

headform, both points located on the median

plane of the helmet.


Head Form (ASTM F 429) Basic Plane

Includes the superior rims of theauditory measures (the upperedges of the external openings ofthe ears) and the notches of theinferior orbital ridges (thebottom of the eye sockets).

Crown

A point in the median planewhich is equal chord lengthsfrom the anterior and posteriorintersections of the median andreference planes.

Coronal Plane

A vertical plane that isperpendicular to the median andreference planes and passesthrough the crown of the headform (lateral plane).

Median Plane

A vertical plane that passesthrough the head form fromfront to back and divides it intoright and left halves (mid-sagittalplane).

Reference Plan

A plane that is located at aspecified distance above andparallel to the basic plane.


Summary of Test Method

(ASTM F 429)


Schematic of Typical Drop Assembly

• The headform shall be attached to the

free-fall drop assembly carriage by an

adjustable mounting which will allow

impacts to be delivered to any

prescribed point on the helmet

• A headgear is mounted on a headform

that is oriented in different positions

and is dropped at a specific velocity

onto an impact surface.

• A linear accelerometer mounted at

the center of gravity of the headform

monitors the acceleration and the

time history of impact which are

recorded with appropriate

instrumentation.

Apparatus for Testing (ASTM F 429) Acceleration Transducer

The acceleration transducer is mounted

at the center of gravity of the combined

test headform and carriage assembly

with the sensitive axis aligned to within

5° of the vertical when the helmet and

headform are in the impact position.

System Accuracy

The impact recording system shall be

capable of measuring shocks of up to

500 g peak acceleration with an accuracy

of + 5 %.

Impact Recording

The impact shall be recorded on single-

or dual-trace storage oscilloscope with

0.1mV to 20 V deflection factor, 1 to 5-

ms sweep speed-division, and 500-kHz

bandwidth.

Headforms

The test headforms to be used for helmet

impact testing are Size A, E, J, and M

headforms as described in ISO/DIS 6220.

Height Measuring Rod

A metal rod accurate to + 0.10 in. (+ 2.5

mm) shall be used for measuring drop

heights.

Impact Surfaces

The impact surface for the instrument

system check shall be a flat, Modular

Elastomer Programmer (MEP), 152 mm in

diameter and 25 mm in thickness.

Spherical Impactor

A device made of low resonance material,

for example, magnesium, aluminum alloy or

stainless steel, that couples mechanically

with the ball arm connector of the drop

assembly in place of the impact test

headform.


Conditioning (ASTM F 429)

AmbientTemperature (4 hours)

Temperature: 21 + 5oC

Relative Humidity: 50 + 15%

Low / HighTemperature Cycle (each 4 hours)

LowTemperature: -20oC

HighTemperature: 50oC

Water Immersion (4 - 24 hours)

Temperature: 21 + 5oC

Testing for Conditioned Specimen

All testing condition with 5 min after the removal from

the conditioning environment. All test must remain in

the conditioning environment for a minimum of 15 min.


Impact Requirement

(ASTM F 717)1. Each helmet model presented for impact testing shall

be furnished with a reference index (from the lowest

point of the helmet face opening to the basic plane of

a reference head form) as established by the helmet

manufacturer.

2. Internal shock-absorbing components of the helmet

shall not become detached or loose during impact

tests or show permanent deformation or physical

damage.

3. A test report of impact tests as described in the

Report Section of Test Method F 429 shall be an

integral part of this specification.


Impact Test Locations

(ASTM F 429)


Front

Located in the median plane and 81.8

mm above the anterior intersection of

the median and reference planes.

Front Boss

A point in a plane 45° (0.78 rad) from

the median plane as measured in a

clockwise direction and 56.3 mm

above the reference plane.

Side

Located at a point 30.9 mm above the

intersection of the reference plane and

the coronal plane, and 90° (1.57 rad)

in a clockwise direction from the

anterior intersection of the median

and reference planes.

Impact Test Locations

(ASTM F 429)


Rear Boss

A point in a plane 135° (2.36 rad) in

a clockwise direction from the

anterior intersection of the median

and reference planes, and 30.9 mm

above the reference plane.

Rear

A point 30.9 mm above the

posterior intersection of the median

and reference planes.

Crown

A point in the median plane that is

equidistant from the anterior and

posterior intersections of the

median and reference planes.

Report Testing Form


Product Marking & Labeling

(ASTM F 717)1. Each helmet shall be provided with instructions for proper

sizing and adjustment.

2. Each helmet shall be permanently labeled with the following

items:

Identification of the manufacturer.

Un-coded date of manufacture.

Model designation

Size or size range

Warning concerning improper cleaning agents & paints.

3. The user shall be provided with a warning on a permanent

label concerning improper attachment or application of

hardware, such as face masks, that would compromise the

shock absorbing abilities of the helmet.


Reference

ASTM F 717 (Standard Specification for Football

Helmets).

ASTM F 429 (Shock-Attenuation Characteristics of

Protective Headgear for Football).

http://en.wikipedia.org/wiki/Football_helmet

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