Recommended Operating,
Care (Maintenance) And
Inspection Manual
For
Synthetic Web Tie Downs
WSTDA-T-2
© Web Sling & Tie Down Association 2017
© Web Sling & Tie Down Association. All rights reserved. No part of
this publication may be produced, stored in a retrieval system, or
transmitted, in any form or by any means, electronic, mechanical,
photocopying, recording or otherwise, without the prior permission of
the Web Sling & Tie Down Association. This publication is circulated
subject to the condition that it shall not, by way of trade or otherwise,
be lent, sold, hired out or otherwise circulated without WSTDA’s prior
consent.
MANDATORY AND ADVISORY RULES
Mandatory rules are characterized by the use of the word
“shall”. If a rule is of an advisory nature, it is indicated by the use of
the word “should”, or it is stated as a recommendation.
The Web Sling & Tie Down Association has also formulated a
Recommended Standard Specification for Synthetic Web Tie Downs
as a guide for users, industry and government to assist in the proper
use, maintenance and inspection of synthetic web tie downs.
The Association suggests the use of the Recommended
Standard Specification for Synthetic Web Tie Downs WSTDA-T-1 by
all synthetic web tie down users.
Figures shown in this standard are for illustrative purposes only and
are not intended to represent usage, design or manufacturing
processes.
Web Sling & Tie Down Association, Inc.
9 Newport Drive, Suite 200
Forest Hill, MD 21050 U.S.A
Tel. (443) 640-1070
Fax (443) 640-1031
Email: wstda@stringfellowgroup.net
Web Site www.wstda.com
First Published and Copyright 1995
First Revision 2000
Second Revision 2007
Third Revision 2017
TABLE OF CONTENTS
Introduction…………………………………………………… 1
Synthetic Web Tie Downs…………………………………... 2
Synthetic Web Tie Down Identification……………………. 2
Recommended Operating Practices
Proper Selection……………………………………. 3
Use and Care………………………………………. 4
Environmental Considerations…………………… 5
Inspection, Removal, Repair
Inspection…………………………………………… 8
Removal from Service…………………………….. 9
Repair………………………………………………. 11
INTRODUCTION
The Web Sling & Tie Down Association (WSTDA) is a tax-exempt,
non-profit, technical association dedicated to the development and
promotion of voluntary recommended standards and associated
reference materials. Originally established in 1973 as the Web Sling
Association (WSA), the WSA serviced the synthetic web sling
industry. In 1988, the WSA further defined its purpose to include
synthetic web tie downs and became the Web Sling & Tie Down
Association. Today, members of the WSTDA include manufacturers
and suppliers of synthetic web slings and tie downs, roundslings,
synthetic webbing, fibers, thread and related components.
It is an industry organization of manufacturers of synthetic yarns,
webbing, slings, tie downs and related components. These products
are used in the manufacturing, transportation, recreation, construction
and forestry industries and by the military and governmental agencies,
for lifting, lowering, moving and securing loads.
The WSTDA’s mission is to foster and further, in every lawful manner,
the common interests of its members and industry. In pursuance of
this mission, the association has prepared this manual. It is intended
to serve as a general outline of recommended procedures and
suggested operating practices and is not intended to be an all-
inclusive list of procedures for specific products or applications.
Accordingly, the Web Sling & Tie Down Association, Inc. disclaims
any responsibility for the actual use of any synthetic web tie down
products. The user should consult the manufacturer for further
information concerning the proper care and use of its products.
1
SYNTHETIC WEB TIE DOWNS
The use of “web tie down” throughout this publication shall be defined
as a synthetic web tie down which is fabricated of synthetic webbing,
with or without hardware, for the purpose of securing cargo. Web tie
downs made from materials or construction other than those detailed
in this Recommended Standard Specification shall be used in
accordance with the recommendations of the web tie down
manufacturer or qualified person.
Safety is the paramount consideration involved in the use of any web
tie down. The appropriate web tie down shall be selected by the user
for the specific application. Users of web tie downs shall have
knowledge on the proper method of cargo securement. Users shall
also be knowledgeable about federal, state, provincial, local and
industry regulations applicable to cargo securement.
Figures shown in this standard are for illustrative purposes only and
are not intended to represent usage, design or manufacturing
processes.
SYNTHETIC WEB TIE DOWN IDENTIFICATION
EACH WEB TIE DOWN ASSEMBLY (OR SUB UNIT, IF IT IS
INTENDED THAT PARTS BE SEPARABLE) SHALL BE DURABLY
MARKED OR LABELED BY THE MANUFACTURER USING AN
IDENTIFICATION TAG, STENCIL OR OTHER MEANS WITH THE
FOLLOWING REQUIRED INFORMATION:
A. Name and/or trademark of the web tie down manufacturer
B. Working load limit in pounds and kilograms
2
RECOMMENDED OPERATING PRACTICES
Proper Selection
Select a web tie down having suitable characteristics for the type
of load, environment and attachment to vehicle anchor point.
Fittings shall be the proper shape and size to ensure that they will
attach properly to the vehicle and cargo anchor / attachment
points.
Identify the working load limit (WLL) marked on the web tie down.
Identify the working load limit (WLL) of the vehicle and cargo
anchor / attachment points. If no rating is visible contact the owner
or vehicle manufacturer for tie down instructions. The lesser rated
working load limit (WLL), whether that is the anchor point or the
web tie down, shall determine the working load limit (WLL) of the
entire securement system.
Determine the proper number of web tie downs required based on
the weight of the cargo, the type of commodity, the aggregate
working load limit of the securement system and the length/weight
ratio of the cargo being secured. The tie down angle should also
be considered.
Determine the proper number of web tie downs required based
upon the weight of the cargo, the type of commodity, the
aggregate working load limit of the securement system and the
length/weight ratio of the cargo being secured.
Additionally, end users and enforcement personnel are required to
know commodity-specific rules governing proper web tie down
determination as published by the Federal Motor Carrier Safety
Administration Standard for Protection Against Shifting and Falling
Cargo; Final Rule effective June 22, 2006 or latest ruling, and/or
Canadian Council of Motor Transport Administrators, National
Safety Code Standard 10, amended June 2013 or current
regulations in effect.
3
Use and Care
Web tie downs shall not be loaded in excess of the working load
limit provided by the manufacturer. Consideration shall be given to
the angle from the horizontal (web tie down to trailer) that affects
the downward pressure.
Effect of Angle - Example: If using web tie downs at 30 degrees
the effective downward pressure is reduced to 50% of the vertical
strap assembly efficiency. Multiply the working load limit (WLL) by
50% to get the reduced effectiveness of the web tie down and add
additional web tie downs necessary to secure the load properly.
The effectiveness examples pictured below are only true of
indirect tie downs.
Web tie downs shall be attached to the vehicle and positioned in
accordance with applicable regulations for the commodity being
transported to prevent shifting and/or loss of cargo.
Web tie downs shall always be protected from corners, edges,
protrusions and abrasive surfaces with edge protection that resists
abrasion, cutting or crushing.
Web tie downs shall not be shortened, joined, repaired or
lengthened by being tied in knots.
4
Web tie downs designed to secure cargo shall not be used for
lifting, lowering or suspending cargo or for towing.
When using winch or ratchet straps, a minimum of two (2) and a
maximum of four (4) wraps of webbing shall be on the winch or
ratchet mandrel. Excessive wraps of webbing on the mandrel may
reduce the working load limit of the web tie down and may
interfere with proper operation. Not enough wraps and the
webbing may not reach optimal tension.
Before operating any web tie down, the user shall secure his/her
footing to prevent slipping or falling. In adverse weather
conditions, including freezing temperatures, additional caution
should be exercised.
Web tie downs shall be used, inspected and adjusted during the
transportation of cargo per applicable federal, state, provincial,
local and industry regulations.
Web tie downs should not be pulled from under cargo when the
cargo is resting on the web tie down.
Web tie downs should not be dropped or dragged on the floor,
ground or any abrasive surface.
Environmental Considerations
Web tie downs should be stored in a cool, dry and dark place
when not in use to prevent loss of strength through exposure to
ultra-violet light.
Chemically-active environments can affect the strength of web tie
downs in varying degrees ranging from little to total degradation.
The web tie down manufacturer, or qualified person, should be
consulted before any web tie down is used or stored in chemically-
active environments.
Web tie downs incorporating aluminum fittings shall not be used
where fumes, vapors, sprays, mists or liquids of alkalis and/or
acids are present.
5
Acids
Nylon is subject to degradation in acids ranging from little to total
degradation.
Polyester is resistant to many acids but is subject to degradation
ranging from little to moderate with some acids.
Each application shall be evaluated, taking into consideration the
following:
a. Type of acid c. Concentration
b. Exposure conditions d. Temperature
Alkalis
Polyester is subject to degradation in alkalis ranging from little to
total degradation.
Nylon is resistant to many alkalis but is subject to degradation
ranging from little to moderate with some alkalis.
Each application shall be evaluated, taking into consideration the
following:
a. Type of alkalis c. Concentration
b. Exposure conditions d. Temperature
Temperatures
Web tie downs using nylon or polyester webbing shall not be used
at temperatures in excess of 194 degrees F (90 degrees C) or
below -40 degrees F (-40 degrees C).
Web tie downs using nylon or polyester webbing shall not come in
contact with any object with a temperature in excess of 194
degrees F (90 degrees C) or below -40 degrees F (-40 degrees
C). This includes the cargo being secured, the vehicle and the
anchor points.
6
Ultra-Violet Light
Environments in which web tie downs are continuously exposed to
ultra-violet light affect the strength of the web tie downs in varying
degrees ranging from slight to total degradation.
Factors that affect the degree of strength loss:
1. Length of time of continuous exposure
2. Webbing construction and design
3. Other environmental factors such as weather conditions and
geographic location
Suggested procedures to minimize the effects of ultra-violet light:
1. Store web tie downs in a cool, dry and dark place when not in
use
2. Consult web tie down manufacturer for coatings that may be
applied to the webbing
Some visual indications of possible ultra-violet light degradation
are:
1. Bleaching out of webbing color
2. Increased stiffness of webbing
3. Surface abrasion in areas not normally in contact with the load
CAUTION: Degradation can take place without visible indications.
If in doubt, contact the web tie down manufacturer for a possible
proof load test or simply remove from service.
Web tie downs and associated hardware may be subjected to dirt,
mud, snow, road salt, cleaning solutions, etc. Frequent inspection,
cleaning and lubrication as appropriate will help ensure proper
operating condition. Aluminum fittings should not be cleaned with
chlorine-based cleaning agents or used in high chlorine
environments.
Washing of tie down webbing (including pressure washing) is not
recommended as any washing can cause accelerated degradation
of the webbing and loss of strength due to mechanical/chemical
damage.
7
INSPECTION, REMOVAL AND REPAIR
For the purpose of this chapter, a designated person is defined as
personnel selected or assigned by the employer as being
competent to perform specific duties.
A qualified person is one who by possession of a recognized
degree, certificate of professional standing or by extensive
knowledge, training and experience has successfully
demonstrated the ability to solve or resolve problems related to
the subject matter and work.
Type of Inspections
Initial Inspection
Prior to use, web tie downs shall be inspected by a designated
person to verify compliance with the applicable provisions of
this chapter.
Frequent Inspection
(a) A visual inspection for damage shall be performed by
the user or other designated person before each use.
(b) Conditions such as those listed in the removal from
service criteria shall cause a web tie down to be removed from
service. Web tie downs removed shall not be returned to
service until approved by a qualified person.
Periodic Inspection
(a) A complete inspection for damage to the web tie down
shall be performed periodically by a qualified person. Each
web tie down shall be examined individually, taking care to
expose and examine all surfaces and components. The web
tie down shall be examined for conditions such as those listed
in the removal from service criteria.
8
(b) Frequency of a periodic inspection shall be based on,
but not limited to:
1) Frequency of web tie down use
2) Severity of service conditions
3) Experience gained on the service life of
web tie downs used in similar applications
(c) A written record of periodic inspections should be kept
on file. These records should show a description of the web tie
down, the condition at the time of the inspection, the date the
inspection was performed and the qualified person who
performed the inspection.
Removal from Service
A web tie down shall be removed from service if any of the
following are visible:
a. Holes, tears, cuts, snags or embedded particles which cause
doubt as to the strength of the web tie down.
b. Broken or worn stitching in load-bearing stitch patterns.
c. Abrasion wears.
d. Knots in any part of the webbing.
e. Melting, charring or weld spatter on any part of the webbing.
f. Acid or alkali burns.
g. Signs of ultra-violet light degradation.
h. Pitting, corrosion, cracked, distorted or broken buckles or end
fittings.
i. The working load limit assigned by the web tie down
manufacturer is no longer visible.
j. Any other visible damage which causes doubt as to the
strength of the web tie down.
9
FIGURES – DAMAGED SYNTHETIC WEB TIE DOWNS
10
Repairs of Synthetic Web Tie Downs
No repairs of webbing, fittings, buckles or stitching/sew patterns
shall be permitted.
Web tie downs may be re-webbed utilizing existing hardware if the
tie down manufacturer determines the hardware is reusable.
Each web tie down re-webbed utilizing used hardware shall be
proof load tested to one and one half (1.5) times the working load
limit. The web tie down manufacturer performing the re-web shall
conduct this proof test and a certificate shall be provided to the
user with a copy kept on file by the web tie down manufacturer.
When re-webbed, the web tie down shall be marked with a label to
identify when the re-web was performed and the name or
trademark of the web tie down manufacturer that performed the
work.
Temporary repairs of webbing, fittings or stitching shall not be
permitted.
11
This recommended manual has been formulated as a guide to users,
industry and government to assist in the proper use, maintenance and
inspection of synthetic web tie downs. The existence of this
recommended manual does not however prevent members of the
Web Sling & Tie Down Association, Inc. and other manufacturers from
manufacturing or selling products not conforming to this manual.
