Bsi bs au 200 1a 1984 (2000)

BRITISH STANDARD AUTOMOBILE SERIES CONFIRMED NOVEMBER 1992 BS AU 200 1a 1984 Incorporating Amendment No 1 Spray reducing devices for heavy goods vehicles — Part 1 Specification for design of containme[.]

Spray reducing devices

U C6 9.1 3-1 2.3-7 3.2

This Bri shStan ard, ha ing

b en pre ared u der the

directonof the Automo ile

Stan ards Commi e ,

waspublished u der the

authoriyof the Bo rd of BSI

an comes into efect on

3 Aug ust1 8

© BSI0 -2 0

The folowing BSI references

relate to the work on this

stan ard:

Commi e reference AUE/13

Draft for comment8 /76 3 DC

ISBN 0 5 0 1 9 7 7

The prep ration of this BritishStand rd was entrusted b the Automobi e

Stand rds Commit e ( AUE/ -) to Tech ical Commit e AUE/13 upon which

the folowing bodies were represented:

Dep rtment of Transport

Freig ht Transport Association Limited

Institute of Roa Transport Eng ine r ( Incorporated)

Lond on Transport Executiv e

National Bus Comp ny

National Freig ht Corporation ( NFC) Ltd

Roa Haulag e Association Ltd

Society of Motor Man facturer and Tra er Limited

The fol owing bod ies were also represented in the d rafting of the stand ard,

throug h subcommit e s an p nels:

British Ag g reg ate Construction Materials Industries

British Rub er Man facturer ’ Association

Dep rtment of the Env ironment ( Transport an Roa Resear h La oratory )

Institute of Petroleum

Motor Ind ustries Resear h Association

Ministry of Defence

Univ er ity of Southampton

Vehicle Buider ’ and Rep irer ’ Association

Co pted member

Am endm ents is ued sinc publ cation

Amd No Date of is ue Comments

5 4 August 19 6 Indicated b a sidelne in the marg in

Commit e s responsible Inside font cov er

Section 1 General

Section 2 Containment and spra sup res ion

d ev icesformingconv entionalty pes of whe l g uarding

Section 3 Containment and spra sup res ion

d ev ices for some non-ste ra le whe ls

Section 4 Containment sy stems forming an alternativ e

tothev alancesandsup res ion d ev ices in section 2

Fig ure 1 — W id th of whe l g uard and position

Fig ure 2 — W he l g uards, whe l fla s andouter

v alancesforsing lea lesan multiplea leswhere

Fig ure 3 — W he l g uard s, whe l fla s and outer

v alances for multiple a les where the d istance

Fig ure 5 — W he l g uard s, whe l fla s and outer

v alances using air/ water sep rator for multiple ax les

Fig ure 6 — W he l g uard s, whe l fla s and outer

v alances using air/water sep rator for sing le a les

and multiple a les where the d istance betwe n ty res

This BritishStand ard has be n prep red u der the direction of the Automobie

Stand rd s Commit e at the req uest of the Dep rtment of Transport to specify

req uirements for dev ices to control spra f om heav y g oods v ehicles

The problem of spra is so complex and ex cerb ted b many factor , that ev en

the fit ing of ful comprehensiv e spra reducing d ev ices is u l kely to total y

el minate spray Howev er, it has be n shown that v ision f om an ov ertaking

v ehicle can be sig nificantly improv ed when spra red uction dev ices are fit ed to

heav y g ood s v ehicles In ad dition the rearward v ision f om these v ehicles is

simiarly improv ed , so that the ov ertaking v ehicle is more v isible to the driv er

Spra is g enerated b the interaction betwe n v ehicle ty res and a wet road

surace The d ensity of the spra cloud produced wi l v ary fom point to point

within the cloud but in g eneral it is dependent on factor such as the d epth of

surace water,v ehicle siz and desig n,spe d and the d irection an v elocity of the

wind It is also afected b roa surace desig n and special perv ious roa sur aces

can help red uce spray Howev er, these are not v ia le for g eneral road use at the

time of publshing this stand rd which in any case only cov er improv ements in

v ehicle desig n

Resear h has shown that spra only becomes objectiona le an sig nificant

a ov e5 mie/ h( 80km/h) and that l g ht v ehicles trav el ng at spe d s

below7 mie/ h( 11 km/ h) d o not normaly g enerate suficient spra to ad d to

this problem The problem is caused b spra being g enerated at such a heig ht

and d ensity that v isibi ty is seriously imp ired for other roa user and the rear

v ision of the driv er of the spray -producing v ehicle can also be reduced Und er the

wor t d riv ing cond itions the wind sc e n wiper can ot in g eneral maintain a

clear winds re n so ag g rav ating the problem

The whe l siz an combination of a les of larg er g oods v ehicles, tog ether with

their po r aerod y namic per ormance, make them the most sig nificant spra

g enerator , p rticularly when trav el ng at ov er5 mie/h( 80km/h) Most work

on spra reduction has therefore be n directed at this g roup of v ehicles

Tests hav e shown that thre aspects of v ehicle desig n can hav e a sig nificant efect

in the reduction of spra an these are as folows:

a) containment arou d the whe ls, i.e.cor ectly desig ned whe l g uards,

v alances and whe l fla s;

b) fit ing sup res ion dev ices which help prev ent surace water thrown up b

the ty res forming spray ;

c) p y ing d ue reg ard to the aerody namic characteristic of v ehicles

Each of these aspects is a dres ed sep rately in this stand rd but it should be

recog niz d that a sy stem using a combination of al thre method s is much more

lkely to be efectiv e than any sing le ty pe of dev ice

W hist this BritishStand ard a ples specificaly to heav y g oods v ehicles and their

traier its principles ma be used for other v ehicles when simi ar problems oc ur

BSAU20 -2a specifies the perormance requirements of sup res ion material

and dev ices, and air/ water sep rating material an dev ices

A British Stand ard d oes not purport to includ e al the neces ary prov isions of a

contract User of British Stand rd s are responsible for their cor ect a plcation

Com pl anc with a British Standard does not ofitself confer im m unity

f om leg al o l g ations

Sum mary of pag es

This document comprises a f ont cov er, an insid e font cov er, p g esi andi ,

p g es1 to10, an inside b ck cov er and a b ck cov er

This stand rd has be n up ated ( se copy rig ht d ate) an ma hav e ha

amendments incorporated This wi l be indicated in the amendment ta le on the

inside f ont cov er

Section 1 General

1 Scope

This Part of BSAU20 specifies req uirements for

d ev ices which are fit ed to motor v ehicles and

traier for the purpose of control ng spra which is

g enerated betwe n the v ehicle ty res an a wet road

sur ace

Req uirements for containment and sup res ion

d ev ices in the form of “ conv entional” ty pes of whe l

g uards with v alances and whe l fla s for motor

v ehicles hav ing a ma imum g ros mas

exce d ing7.5t, articulated tractor u its hav ing a

train mas exce ding7.5t an traier hav ing a

ma imum g ros mas exce ding3.5t are specified

in section2

Req uirements for containment and sup res ion

d ev ices which ma be fit ed as alternativ es to the

d ev ices dealt with in section2 when conv entional

ty pes of whe l guard s are not used, but the whe ls

are alway s cov ered b the flo r of the v ehicle body ,

are specified in section3 Section3 a pl es only to

non-ste ra le rear whe ls on sing le an multiple

a les of motor v ehicles hav ing a ma imum g ros

mas exce ding7.5t and to trai er hav ing a

ma imum g ros mas exce ding3.5t

Alternativ e requirements for v alances and whe l

fla s for use on the containment dev ices d ealt with

in section2 for the ty pes of v ehicle refer ed to in

that section are specified in section4

NOT 1 App n ix A contains g eneral comment relatng to

a rodynamic styling

NOT 2 The t le of the publicaton refered to in this stan ard

is g iv n on the inside b ck cov er

2 Definitions

For the purposes ofthis Part of BSAU20 , the

fol owing d efinitions a ply

2.1

containm ent devic

a dev ice intend ed to contain the water which is shed

b the v ehicle tyre and to return it to the roa

sur ace at a low v elocity

2.2

whe l g uard (m udg uard)

that p rt of the containment dev ice which is

desig ned to restrict or prev ent surace water,which

is shed b the v ehicle’s ty res, f om being projected

awa f om the v ehicle

NOT 1 The whe l g uard ma b p rt of the b dy structure

NOT 2 W he l g uards should red ce the dang er an also

pro ide protecton as far as p s ible to other ro d user fom

stones, mu , ice an snow thrown up b the tyres

2.3

v lanc

that p rt of the containment dev ice in or

a proaching the long itudinal v ertical plane of the

v ehicle

2.4

whe l fla

that p rt of the containment dev ice at ached to the

u d er ide of the v ehicle or the whe l g uard to form

an extension towards the roa sur ace, behind the

whe l, in or a proaching the plane normal to the

long itud inal planes of the v ehicle

2.5

suppres ion devic

a d ev ice or material d esig ned to a sorb or dis ip te

the energ y of water thrown f om the ty re in order to

reduce the deg re to which the water shat er into

fine d roplets on hit ing a sur ace

NOT I ma form p rt of the containment dev ice

2.6

air/water separator

a dev ice forming p rt of the v alance and / or whe l

fla which permits air to flow throug h whi st

reducing the emis ion of spra

2.7

l fting a le

an a le which ma be raised f om the roa surace

in the normal cour e of v ehicle operation

2.8

the brea th of that p rt of the ty re which contacts

the road u der normal conditions of use measured

at 9 ° to the peripheral lne of the trea

Spra reducing dev ices shal be in ac ord nce with

the fol owing

a) Spra red ucing dev ices for motor v ehicles

hav ing a ma imum gros mas exce ding7.5t,

for articulated tractor u its hav ing a train mas

exce ding7.5t and for trai er hav ing a

ma imum g ros mas exce d ing3.5t, except for

the case d etaied inb), shal comply with either

section2 or section4

b) Spra reducing d ev ices for non-ste ra le rear

whe ls fit ed to motor v ehicles hav ing a

ma imum g ros mas exce d ing7.5t an to

traier hav ing a ma imum g ros mas

exce ding3.5t and where the whe ls are

normal y cov ered b the flo r of the v ehicle bod y

shal comply with section2 or section3 or

section4

4 Desig n f atur s

4.1 General Containment d ev ices shal be

d esig ned not to d mag e ty res

NOT I is es ental that containment de ices p rmi ade uate

air flow arou d tyres an brake h b as emblies to a oid

o erhe tng

4.2 Lifting a les W here a v ehicle is fit ed with a

l fting a le or a les the containment d ev ice shal

cov er:

a) al whe ls when the lfting a le is lowered; and

b) the whe ls remaining in contact with the roa

when the lfting a le is raised

4.3 Piv ting a les W here an entire a le is

centraly piv oted , so that it can mov e in a horiz ntal

ar , the containment d ev ice shal comply with the

requirements for non-ste ra le whe ls if mou ted

on the piv oting section I it is not mou ted on the

piv oting section, it shal comply with the

req uirements for ste ra le whe ls

4.4 Position of outer v lanc For ste ra le

whe ls, the d istance betwe n a long itudinal plane

touching the outer edg e of a ty re an the inside

edg e, or the inside ed g e of any l p, of the outer

v alance shal not exce d10 mm

For non-ste ra le whe ls, the d istance betwe n a

long itudinal plane touching the outer ed g e of a ty re

an the insid e edg e of the outer v alance shal not

exce d7 mm u les the ra ius ofthe lower edg e of

the outer v alance specified in7.1 and12.2 d oes not

exce d1.0R, in which case it shal not

exce d10 mm ( se Fig ure 1)

NOT I is recommen ed that in er v lances should b

prov ided whene er practca le

5 Condition ofvehicle

For the purposes of the requirements of this

stand ard, the v ehicle shal be in the folowing

cond ition

a) The v ehicle shal be without loa , with

body work an in ru ning ord er ( including

co lant, ois, fuel,to ls, sp re whe l and a d riv er)

For the tractor u it of an articulated v ehicle, the

trai er shal be at ached, for v ehicles fit ed with

d emounta le bod sy stems, an empty bod shal

be at ached In al cases, the whe ls shal be in

the straig ht ahea position

b) In the case of semi trai er for articulated

v ehicles, the loa platform shal be horiz ntal

c) Ty res shal be in nominal y new condition For

the purpose of determining the brea th, the

la el ing ( marking ), decorations, protectiv e

b nd s or ribs on ty re wal s shal not be included

The ty re bread th shal be measured at the heig ht

of the whe l centre

Section 2 Conta inment and spray

suppr s ion devices forming

conventiona l types ofwheel g uarding

6 Wheel g uards

6.1 The whe l g uard shal be positioned to cov er the

area d irectly a ov e, to the font and to the rear of

the ty re( s) as fol ows

a) For sing le a les an multiple a les where the

distance betwe n ty res on a jacent a les is

g reater than3 0mm, the font ed g e ( Fig ure 2

pointC) shal extend forward to reach a lne such

that Ú=3 ° ma imum for ste ra le whe ls or20°

ma imum for non-ste ra le whe ls a ov e the

horiz ntal an p s ing throug h the whe l centre

The rear edg e ( Fig ure 2 pointA) shal ex ten

downwards so that it is not more than10 mm

a ov e a horiz ntal lne throug h the whe l centre

b) In the case of multiple a les where the distance

betwe n the ty res(d ) on a jacent a les is not

more than3 0mm, the whe l g uard shal be in

ac ord nce with Fig ure 3

N T This a plies for two or more a les

NOT Dimensionsb an t are me sured at h b heig ht,

Fig ure 1 — Width of whe l g uard and

positionof outer v lanc

c) The ov eral wid th, q ( se Fig ure 1), of the whe l

g uard shal be at least suficient to cov er the total

ty re brea th, b, or the total bread th of two ty res,

t, in the case of twin whe ls, taking into ac ou t

the ex tremes of ty re/whe l combinations g iv en b

the v ehicle man facturer

6.2 W here whe l g uards consist of sev eral

components, there shal be no g aps betwe n or

within indiv id ual p rts when as embled that wi

permit the exit of spra when the v ehicle is in

motion

7 Outer va lances

7.1 For sing le a les and multiple a les where the

d istance betwe n ty res on a jacent a les is g reater

than3 0mm, the lower edg e of the outer v alance

shal not ex ce d the fol owing d imensions and ra i

f om the centre of the whe l ( se Fig ure 2)

7.2 In the case of multiple a les where the distance

betwe n the ty res on a jacent a les is not more

than3 0mm, the outer v alances in the sp ces

betwe n a les shal fol ow the contour as specified

in7.1an exten d ownwards so that either they are

not more than15 mm a ov e the horiz ntal l ne

throug h the whe l centres or the horiz ntal d istance

betwe n their lower extremities is not more

than6 mm ( se Fig ure 3)

NOT The o tmum con i on is that there should not b a

radial g ap b twe n the lower edg e of the outer v lance an the

cir umference of the ty re, i.e.a v lue of R,or les Howe er, i is

ac e ted that this ide l is not alwa s practca le b aring in min

the alowances neces ary for susp nsion an ste ring mo ement

plus the closenes of some tyres to the edg e of v hicles built to the

leg aly ermi ed width limi

7.3 The d epth of the outer v alance shal be not les

than4 mm to the rear of the v ertical centre lne of

the whe l

NOT The de th of v lances ma b prog res iv ly red ced

forward of the whe l centre

Fig ure 2 — Whe l g uards, whe l fla s and outer v lanc s for sing le a les and

m ultipleaxleswhere the distanc betwe n tyres is g reater than3 0m m

Ste ra ble whe ls

Front ( lea ing ) ed g e( 30° point) R

v

=1.5R

Rear ( trai ing ) edg e( 10 mm point) R

v

=1.5R

Top ( d irectly ov er top of ty re) R

v

=1.5R

Non- ste ra le whe ls

Front ( lead ing ) edg e( 20° point) R

v

=1.25R

Rear ( trai ing ) edg e( 10 mm point) R

v

=1.25R

Top ( directly ov er top of ty re) R

v

=1.25R

where

R is the rad ius of the ty re fit ed to the v ehicle;

R

v

is the rad ial distance of the lower ed g e of

the outer v alance

7.4 There shal be no opening s in outer v alances or

betwe n outer v alances an whe l g uards that al ow

spra to be emit ed

8 Wheel fla ps

8.1 There shal be no g aps betwe n the lower rear

edg e of the whe l g uard and whe l fla s that wi

permit the exit of spray

8.2 A whe l fla shal be of suficient width to cov er

the total ty re brea th, b or t as a plca le

( se Fig ure 1), taking into ac ou t the extremes of

ty re/whe l combinations g iv en b the v ehicle

man facturer, except where the whe l fla is

contained within the whe l g uard when it shal

cov er the brea th of the ty re trea

8.3 The ma imum heig ht of the bot om edg e shal

not exce d a heig ht of either:

a) 20 mm; or

b) 3 0mm for the rearmost a le on traier used

on rol on/rol of fer ies or on any a le where the

ra ial distance of the lower edg e of the outer

v alancing , R

v , do s not exce d the dimensions of

the ra ius of the ty res fit ed to the whe ls on that

a le ( se Fig ure 2)

8.4 The whe l fla shal be not more than3 0mm

fom the rearmost edg e of the ty re except that for

multiple a les where the distance betwe n the ty res

on a jacent a les is les than25 mm, a whe l fla

shal be fit ed only on the rear whe l( s)

( se Fig ure 3) A whe l fla shal be fit ed behind

each whe l where the d istance betwe n the ty res on

a jacent a les is eq ual to or g reater than25 mm

8.5 The rearward deflection of the whe l fla shal

not exce d10 mm when subjected to a for e

of3Nper10 mm of fla width, a pl ed ac os the

width by , for ex mple, a load sprea ing b r, at a

heig ht of5 mm a ov e the bot om of the whe l fla

when it is sup orted in its operating config uration

8.6 The forward facing p rt of the whe l fla shal be

fit ed with a sup res ion material or dev ice that

comples with BSA U20 -2a

In a d ition, the forward facing p rt of the whe l

g uard located below a l ne10 mm a ov e the centre

lne of the whe l shal be fit ed with a sup res ion

material or d ev ice comply ing with BSAU20 -2a to

cov er the bread th of the ty re tread Fig ure 3 — Whe l g uards, whe l fla s and outer valanc s for m ultiple axles

wherethedistanc betwe n tyres is3 0m m or sm al er

Section 3 Containment and spray

suppres ion devices for some

non- steera ble wheels

NOT Reference should b made to clause iemb) for a

complete des ripton of the whe ls cov ered b this secton

9 Outer va lances

9.1 For sing le a les and multiple a les where the

d istance betwe n ty res on a jacent a les is g reater

than or equal to25 mm, the outer v alance shal

cov er the area extending f om the u der id e of the

bod y to a lne formed b the tang ent at the top of the

ty re( s) and betwe n the outer edg e of the whe l fla ,

with which it shal form a seal, an the v ertical

plane formed b the tang ent at the f ont of the ty re

[ se Fig ure 4( a)] In the case of multiple a les, an

outer v alance shal be fit ed ov er each whe l

9.2 There shal be no g aps betwe n the outer

v alance and the u d er ide of the bod that wi

permit the exit of spray

9.3 W here whe l fla s are not fit ed behin each

whe l ( se clause10), the outer v alance shal be

contin ous f om the outer ed g e of the whe l fla to

the v ertical lne at the foremost point of the ty re,

pointC [ se Fig ure 4( b)] on the lead ing a le

9.4 The whole in er face of the outer v alance, the

d epth of which shal be not les than10 mm, shal

be fit ed with a sup res ion material that compl es

with BSAU20 -2a

10 Wheel flaps

W he l fla s shal extend to the u der ide of the

v ehicle structure The whole of the forward facing

p rt of the whe l fla shal be fit ed with a

sup res ion material or dev ice that comples with

BSAU20 -2a There shal be no g aps that wi

permit the exit of spra and the whe l fla s shal

also comply with8.2,8.3,8.4 and8.5

Section 4 Conta inment systems

forming an a lterna tive to the va la nces

a nd suppres ion devices in section 2

11 Wheel g ua rds

1 1 W he l g uards shal comply with6.1 c) and6.2

1 2 W he l g uards for sing le a les an multiple

a les where the d istance betwe n ty res on a jacent

a les is g reater than3 0mm shal comply

with6.1a)

1 3 In the case of multiple a les where the d istance

betwe n ty res on a jacent a les is not more

than3 0mm, the whe l g uard shal be in

ac ord nce with Fig ure 5

N T This a plies for two or more a les

12 Outer va lances

12.1 V alances shal hav e air/water sep rating

material on their lower edg es

Fig ure 4 — Config uration of v lanc s