開放目地形オープンジョイント(OPEN DRAINED JOINT)の水密性能評価における試験方法の影響について

[nt

N]

UDC:699.82:691:69.001.4

JouTual

of

Structural

and

CoEstruction

Engineering

(Transactions

of

AIJ)

No.

397,

Ma[ch,

19S9

Hptem\ftmxxxas!vagfi

M397e

･19894

3

n

VARIABILITY

OF

PERFORMANCE

OF

OPEN

DRAINED

JOINTS

UNDER

DIFFERENT

DRIVING

RAIN

TESTS

.

by

HIROZO

ISHIKAWA',

Member

of

A.I.J.

1.

Introduction

'

It

is

well

known

that

wind

_pressure

_plays

an

important

role

in

rain

_penetration

_through

cracks

of

defeetive

joints

on

'

walls.

In

the

design

of

open

drained

joints,

however,

other

factors,

such as

kinetic

energy

of

raindrops

or airstream along

the

wall surface, should also

be

considered

as

forces

which

drive

rain water

into

the

joints,

Static

pressure

boxes

which usually

incorporate

spray nozzle

systems

have

so

far

been

extensively used

for

testing

the

weathertightness of windows and external wall units,

As

far

as

the

open

drained

joint

designs

are concerned,

the

adequacy of such a

test

method

is

apparently

doubtful,

because

neither such

bexes

can

_produce

the

actual air stream over

the

test

wall nor can

the

spray nozzles

control

the

kinetic

energy of

the

water

drops,

'

The

so-ealled

dynamic

test

method, which employs a

blast

from

a wind

_generator

in

which water

drops

are released, obviously

_provides

far

more realistic rainstorm conditions

in

this

respect.

Earlier

apparatus

which utilized an aircraft engine

and

_propeller

for

the

wind

_generator

tended

to

lack

the

accuracy needed

for

_the

control of

test

conditions

[

₁

]

.

Research

has

been

done

to

obtain a more reliable

test

apparatus with

this

method

by

using

blowers

which

generate

more eve4 and

tess

turbulent

air

flow

[2,

3].

Attempts

have

been

also made with

the

static

_pressure

box

type

apparatus

to

incorporate

a more realistic raindrop

impinging

condition

by

fitting

mechanism

for

_producing

air-jet

driven

water

drops

[4,

5],

Recently,

the

author attempted

to

develop

a

rainstorrn simulator which retains

the

characteristics of

the

dynamic

test

method

but

which can also

_provide

uniform

and

_precise

test

conditions consistently over

the

test

wall,

and

has

constructed a

_piototype

of such an apparatus

[6].

Because

there

has

been

little

information,

however,

on

the

extent

to

which each of

these

apparatus

simulate

the

naturally exposed condition of external walls

to

driving

rain,

it

is

unclear which of

them

can

_properly

evaluate

the

perfomance

of open

drained

joints.

It

is

the

_purpose

of

this

study

to

investigate

the

behaviour

of

the

artificial rain water

_passed

_threugh

joint

_gaps,

and

the

drainage

_pattern

of

the

rain

water

in

the

cavities of vertical open

drained

joints,

using

two

types

of

driving

rain apparatus:{1) a conventional spray nozzle system with or without

a

static

pressure

box

and

(2>

the

rainstorm

simulator

developed

by

the

author,

in

order

to

find

out

the

necessary

features

of

the

test

method

for

the

weathertightness of open

drained

joints.

2,

TURS

(Tokai

University

Rainstorm

Simulator)

2.1

Design

prin,ciple

Fig,1

shows

the

rainstorm simulator, which was

constructed

at

the

Department

of

Architecture

and

Building

Engineering

of

Tokai

University,

Kanagawa,

Japan.

Artificial

raindrops are

discharged

together

with

an

airstream

frem

a nozzle

fitted

in

a outlet

box,

which moves reciprocally along

the

test

wall,

thus

_providing

uniform wetting over

the

wall surface.

It

was

intended

that

tests

could

be

done

with variations of rain

intensity,

wind speed,

direction

of

rain

impingement

and outlet

traveling

speed,

Mechanical

_problems

had

to

be

overcome

to

make

the

motion

of

the

outlet

constant and

continuous

in

order

to

keep

_the

wetting

rate

uniform

over

the

test

wall.

2,2

Wind

and rain outlet

*

_Professor,

_Department

of

Architecture

and

Building

Engineering,

Faculty

of

Engineering,

Tokai

Uniyersity,

Dr.

Eng.

(ManuscTipt

received

August

l,

1988)

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Fig.1

TURS

(Tekai

'University

RainstormS{mulator)

The

eutlet consists of an airtight

box

and a nozzle section which

is

fitted

on one side of

the

box.

The

opposite side of

the

box

is

connected

to

a

fan

by

a

flexible

duct.

The

nozzle

is

supported

on

a

pair

of

pivots

and

can

be

swiveled

Jound

so

that

the

opening

faces

the

test

wall at an angle

between

+45

and

-45

degrees,

Odegree

being

normat

direction

to

the

wall.

The

nozzle outlet opening

is

1

OOOmm

high

and

100

mm wide.

Fixed

inside

the

nozzle are

five

linear

cone

type

water spray nozzles,

from

which water

drops

are

discharged

towards

the

opening.

Each

water spray nozzle

has

a

O.

5

mm wide vertical slitshaped

orifice,

and

its

horizontal

spray

angle varied

from

150

to

₂₅₀

within

the

range of water

_pressure

applied

in

the

tests.

The

outlet

box

has

two

wheels at

the

bottom

and moves sidewise along

the

_guide

rails supported

by

a steel

frame.

It

is

driv,en

by

achain and an electric motoT

togethei

with a magnetic clutch and reversing

_gears.

The

traveling

distance

is

760

mm on

the

outlet

box

centres,

2,3

The

fan

The

fan

has

a

capacity

of

90

m31min, at a static

_pressure

of

35

mm

Aq,

and

is

driven

by

a

2,

2

kw

variable speed electric motor,

It

can

_produce

a wind speed of

1

to

12

mls at

the

centre of

the

nozzle

opening.

2,4

Water

supply

The

watersupplying

devices,

which are not shown

in

the

figure,

consist

of

a

water

tank,

a

_pump,

a

flow

rate

meter and

flow

adjusting valves.

Water

is

supplied

through

a

flexible

_plastic

tube

to

the

water

inlet

at

the

top

of

the

outlet

box.

The

water supply rate was varied

by

changing

the

water spray

_pressure,

within

the

range of

l.

7

to

3.

4

litres

per

minute,

which corresponds

to

a rain

intensity

of

120

to

240

mmlhr over

the

wall area covered

by

the

traveling

nozzle.

3.

Measurement

of

the

spreading

_pattern

of water

drops

after

passing

through

the

joint

gap

3,1

Joint

models

Two

types

of vertical

joints-butt

joints

and

lap

joints-were

tested.

Fig.

2

shows

the

horizontal

section of

the

joint

models.

As

shown

in

Table

1,

they

were

tested

with several

_gap

widths

_W

(butt

joint)

and

lap

Lengths

L

(lap

joint).

{OUTSIOE) GAP W!DTH

m

=f= == sHA ncRTL[[ sHEET []NS]DE) HUTT JO]NT

-LAP LENGTH

rr

=

LioD.ll

LAP JalNT

Fig.2

Joint

rnedels used

for

spreading

_pattern

test.

8R

sooFAttt-''' L

''

''10.MM

ttt'AFRON

190

n

TOfi

.S

J TRANSPARENT ACRTL]CSHEET CFRDNT)

-PLTblOODFRAHE CR[AR)

T v[EW A-A 5ECIIeN

Fig.3

Rain

catch

_panel

3.2

Rain

catch

_panels

For

the

accurate measurement of

horizontal

spreading

_patterns

of water

drops

_passed

through

the

_joint

_gap,

specially

designed

rain catch

_panels

were

used.

Fig.

3

shows

one of

the

_panels,

which was used

for

butt

joints.

The

panel

consists of

twenty

narrow strips of

transparent

acrylic sheet, which are arranged

in

a row

but

staggered

at

10

mm.

In

the

tests,

the

_panel

was

_placed

behind

the

joint

model, with

its

front

end attached

to

the

rear side of

tlte

model.

After

the

model was exposed

to

the

artificial rain,

the

_panel

was replaced and

_photographs

were

taken

from

behind.

Then

the

distribution

of

the

water

drops

on each strip was carefully examined and recorded.

3,3

Test

methods

Test

conditions are summarized

in

Tablel.

Using

the

TURS

apparatus,

tests

were

done

with various combinations of rain

intensities

Ir,

nozzle

directions

D,

and wind speeds

V.

The

distance

between

the

nozzle outlet and

the

joint

model was

kept

constant

to

₃₀₀

rnm.

With

the

rqin catch

_panel

attached

to

the

back,

the

model was exposed

to

the

artificial rainstorm

for

ten

seconds,

during

which

time

the

outlet completed one return

travel

along

the

model.

The

direction

of

the

nozzle was either

fixed

throughout

_the

_test

_(for

_lap

joints),

er

deflected

to

a certain

degree

to

either side of

the

noTmal

direction,

each on

its

forward

and

backward

movement

(for

butt

joints).

For

the

purpose

of

comparison,

tests

were also

done

by

artificial rain of several

intensities

_generated

by

a spray

system.

The

system

consisted

of

16

full

cone

type

spray nozzles, which were arranged on

four

rows of

horizontal

headers

spaced450 mm

apart,

The

nozzle

diameter

was

1.

6

mm,

and

the

spray angle varied

from

450

to

600

depending

on

the

water

_pressure

applied

in

the

tests.

The

maximum

drop

size was approximately

_2,Omm.

Each

nozzle was

fitted

with a valve.

The

optimum nozzle opening mode and

the

water

_pressure

for

obtaining uniform artficial rain of

desired

intensity

were

determined

_through

_the

_preliminary

_tests.

The

distance

between

_the

nozzles and

the

joint

model was

450

mm

for

the

intensity

of

480

mmlhr, and

750

mm

for

the

intensity

of

240

mmlhr or

less,

The

exposure

time

was

ten

seconds.

After

the

exposure,

the

wet range of each strip of

the

rain

catch

panel

was measured,

Because

the

degree

of

the

wetness

_gradualry

changed at

the

_perimeter

of

the

wet

zone,

it

was necessary

to

set a certain criterion

fer

the

boundary

of

the

wet range,

So,

the

wet range was

determined

to

be

the

surface area of one

5

square centimetre strip covered

by

at

least

_{10discernible}

droplets.

3,4

Test

results

Photo.1

shows an

example

of

the

spread

_pattern

of raindrops, which was recorded on

the

rain catch

_panel

fora

certain

test

condition.

Based

en

the

readings of

the

wet range on each

stTip

of

the

panel,

plans

of

the

spread

_pattern

of

dropaets

which

_passed

through

the

joint

_gaps

were

drawn,

Fig.4

<a)

and

4

<b)

show examples of

the

_plan

of

the

spread

_pattern

obtained

for

a

butt

joint

and a

lap

joint.

Table1

Test

conditions

for

measurement of spreading

pattern

of raindrops after

passing

through

the

joint

gap.ertificta1

rdrin jorimt TUR5 WL lr D [mm)(mr] CmmlhT) t,)[mVs) sprey.?Tstem WL it [mmlCmm) [mm/hr) ,:U,E: ,81g･

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IZO,140, 4BO.]O, 120,240. 4eouf

'tHc

nnxt]e,

Photq1Raindrops

spTeading recorded on

(A

test

by

TURS

method,

butt

gap,

nozzle normai

to

wall, raln

wind speed:8 mls)

Taln]olntint.catch

_panel,

with

10

rnm

:

240

mmlhr,

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Fig.5

Change

of the spreading

_pattern

of raindrops with

joint

_gap

so

(MH) _width.

(Butt

_joints,

_rain

_{intensity:240mmlhr)}

D[PTH SOHM

/bT Spr"adlng pltLe"/ oi ttl/tdrops efter passing thraugh a Lap )elot.

Fig.4

Plans

of spreading

_pattern

of raindrops

after

_passing

thiougb

_joint

gaps.

respectively.

From

these

_plans,

spread angles and maximum

_penetration

widths

(for

butt

joints)

or maximum

penetration

dephts

{for

lap

joints>

were

determined

as shown

in

the

figure.

Here,

aspread angle was measured as

to

the

lines

which

connect

inner

edges of

the

joint

_gap

and

the

border

of

the

wet range at

the

_point

50

mm

behind

the

)elnt.

Fig,

5

shows

the

change of spreading

_pattern

of

raindrops with

the

joint

_gap

width of

butt

joints,

measured

for

two

kinds

of artificial rain,

The

spread angle as well

as

the

_penetration

width

increased

with

both

rain as

the

_joint

_gap

widened,

but

they

were aLways

_greater

in

the

tests

by

TURS

than

in

the

tests

by

the

spray

system.

Fig.6

shows

the

change of spreading

_pattern

of raindrops with

the

lap

length

of

lap

jonts.

Both

the.spread

angle

and

the

penetration

depth

decreased

as

the

lap

length

increased.

It

should

be

noted

that

in

the

tests

by

the

spray

;

10U

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-

S2eO

TESTS BY TURS[D:,45")

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ao

ui

.

TESTS 6Y TURSCD:,AS.1 a

'-

,.,

NO W[ND

a

6o "..<sMts _v[ND

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"'-,

:

:

:

4e NO W[ND

Iioo

TEsTs ",tSMts -]ND

:

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xso

eT

'v...

a- _{BT SPRAT}

'-"

"

SPRAr SYSTEH

x

SVSTEM

ae lo 4o

;Oo

2o 4o LAP LENGTH cMMJ LAP LEHGTH{MM}

Fig.6

Change

of spreading

_pattern

of raindrops with

joint

lap

length.

(lap

joints,

iain

intensity

:

240

mm!hr)

'

-

-eo

:,,,

....--...

I.

k:TNLT:fl:gi?:!i4oHH,HR

l

w[NO SPEED

.."'

:

so a _8Hts/ ax _-ND SPEED

-

.

LJ

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".-."..-"

:

Jt---'IL..eM/s

o

oaO IL

:

NO N,TND

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Mxv

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NO WIND

:

CAP U[OTH:10HH

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l

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-ls

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NDIILE DEFLECI[ON ANGL[ ") NOIIL[ DIRECTrON C')

Fig.7

Change

of the spTeading

pattern

of raindrops with

_Fig.s

_Change

of the spreading

_pattern

of raindrops with

nozzle

deflection

angle.

(Btttt

joint)

the

nozzle

direction.

(Lap

joint)

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Fig.9

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i

s

s

o

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z

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2 "

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1 O4B 12 VIND SPEED CMts)

5

ioo

i;.

g:.

so

klk

lo

4Eu W[ND SPEEDtptls]

Effect

of wind speed on

the

spreading

pattern

of raindTops.

(Rain

intensity

:

240

mmlhr)

Fig.10

g

zso : q

lE!oo

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Effect

of rain

intensity

on the spreading

pattern

of raindrops.

{Tests

by

TURS,

wind speed

:

8

m!s, nezzle normal

to

wall)

system,

_penetration

markedly

decreased

on

a

lap

length

of

15mm

or

more.

whereas

in

the

tests

by

TURS,

penetration

was

less

affected

by

the

increase

in

lap

length.

Figs.

7

and

8

show

the

effect

of

changing

the

nozzle

directi.on

of

the

TURS

apparatus on

the

spread

_pattern

for

both

types

of

joints.

In

the

test

of

butt

joints,

the

further

the

nezzle

direction

deflected

from

the

normal

direction

to

the

wall,

the

_greater

the

maximum

_penetration

width

became,

In

the

tests

of

the

lap

joints,

the

maximlim

_penetration

depth

decreased

as

the

nozzle

turned

from

the

direction

to

which

the

opening

end of

the

lap

joint

is

exposed

to

the

direction

from

which

it

is

shielded.

Figs.

9

and

10

show

the

effects

of wind speed and rain

intensity

by

the

TURS

apparatus on

the

penetration

width or

depth

forboth

types

of

joints.

Penetration

became

more severe as

the

wind speed or rain

intensity

increased

when

the

nozzle

was

directed

normal

to

the

wall.

But

the

effect of wind speed was

negligible

when

direction

of rain

and

wind

impingement

was

deflected

from

the

normal

direction.

This

suggest

that

as

far

as

the

spreading

patterns

are

concerned,

the

effect

of

the

direction

of

impingement

_predominates

the

effect

of

wind speed.

Fig.

11

shows

the

relationship

between

the

rain

intensity

and

the

spread angle

or

the

penetration

width

for

butt

joints

measured

in

the

tests

by

the

spray

system.

Larger

spread

angle

and

_penetration

width

were obtained at

higher

rain

intensities.

Nevertheless,

it

was suspected

that

the

distance

between

the

nozzles and

the

joint

model

had

some relation

to

the

spread

_pattern.

Therefore,

tests

were

done

on a

butt

joint

with various spTaying

distance

at a

fixed

water spray

rate.

The

results are shown

in

Fig,IZ.

Both

the

spread

angle

and

the

penetration

width

linearly

decreased

as

the

spray nozzles receded

from

the

wall.

Considering

the

results,

it

will

be

more appropriate

to

say

that

the

trends

shown

in

Fig.

11

were not

the

direct

influence

of varying spray rate

but

the

effect of changing

the

spray

distance

depending

on

the

spray rate.

3.5

Discussion

100 12D

;

1ooul]e BO2qe< eediormen 40 10 120

Fig.11

;sle'g:::gt!

240 360 4BO 120 Z40 ]EO 4SO

RATN tNTENSITT(HHIHR] RAIN [NTENS[TTtMMtHR]

Change

of the spreading

pattern

of raindreps with

rain

intensity.

(Butt

joints,

tests

by

spray system)

::s::vS

80 60 4D zo BUTT JO[NT

l

250 V[TH 10MH CAP

:

E

. !oo

g

:

!

liO

:

x

t

iOO

4oe Eoo soo 1oooz 2oo 4oo 6oo Boo looo

DISTANC[ BETW[EN SPRAT SYSTEH AND THE WALL (HM)

Change

of

the

spreading

pattern

of raindrops

due

tothe change of

distance

between

the

spray system and the

joint.

(Rain

intensity

240

rnrn!hT at

400

mm

{ront

ef tlte

spray system)

-

23

--200

NII-Electronic Library Service

The

above

results show

that

the

behavior

of

the

simulated raindrops after

passing

through

the

joint

_gap

differ

considerably

depending

_on

_which

_of

_the

_two

_test

_methods

_is

_employed.

_It

_is

obvious

that

the

TURS

is

capable ef

providing

wider range of

driving

rain conditions

than

the

spray nozzle system,

in

that

raindrops

hit

the

wall with variations

in

direction,

kinetic

_energy

_and

density.

_The

_water

_drops

_from

_the

spray nozzles

tend

to

move

Iineaily

even after

_passing

throllgh

the

_joint

_gap

and aTe

likely

to

be

blocked

by

the

overlapping

in

the

joints.

It

is

difficult

to

say

_to

what

extent

the

artificial

dTiving

rain

_produces

raindrop

behaviour

similar

te

actual

driving

rain conditions,

because

little

is

known

_about

_the

_movement

_of

_{actual raindrops}

_in

_joints,

_Herbert

(1974}

reported

the

maximum spread angles of raindrops which

passed

through

vertical

butt

joints

between

_panels

exposed

to

natural weather _conditions

for

_{several months}

_on

_{a wall of a}

_test

_rig

_in

_Plymouth,

_England.

_Measurements

were

done

for

several

joint

_gaps,

two

_panel

thicknesses,

and with or without ventilating

the

cavity

behind

_the

_panel

[7].

His

results with

joints

in

a

₆

mm

thick

_panel

with a vented cavity,

to

which

the

author's

butt

joint

medels roughly resembled, _were

interpreted

_{and reproduced}

in

Fig.5,

_together

_with

_the

_{authoT's results.}

As

seen

in

the

figure,

the

spread

angles

that

were recorded with natural

driving

rains

were

_quite

large

compared with

those

_that

_{were measured with artificial}

_driving

_rains.

_It

_should

_be

_noted,

_however

_that

the

joint

models were exposed

to

the

artificial rains

for

only

ten

seconds.

Wider

spread angles could

have

been

obtained

had

the

exposure

time

been

longer,

since

fine

droplets

scattering at

_the

outer

edge of

the

wet

area

_graclually

accumulate

to

form

larger

drops.

The

spread

angle alone is not sufficient

to

explain

the

behaviour

_{of raindrops}

_passed

_through

joint

gaps.

As

far

as

the

spread

angle

is

concerned,

however,

it

can

be

said

that

the

_behaviour

of artificial raindrops

_generated

by

_the

TURS

is

more

like

that

of natural raindrops

than

those

directly

sprayed

from

nozzles.

4.

Watertightness

te$ts

ot

severa}

vertical open

drained

joints

4.1

Joint

models

Cross

sections

of models of six vertical open

drained

joints,

which were

made

of

transparent

acrylic

sheet, are shown

in

Fig.13.

Joint

A

is

a

_plain-sided

butt

joint,

Joints

B1,

B2,

_and

_B3

_are

plain

sided

butt

joints

with

projecting

edges en

both

sides.

Joints

C

and

D

are

labyrinth

joints.

The

joints

were

1.

96

m

high.

A

water collecting

box

divided

into

several

compartments

was attached

to

the

bottom

of

each

joint

_model,

for

measuring

the

distribution

_{of water}

_that

_penetrated

into

_the

_joint.

_The

gaps

at

the

back

and

the

top

of

the

joint

were

sealed

using adhesive

tape.

Except

for

the

airtight

joints,

the

air seal at

the

back

of

the

_joint

were cut at

three

_positions,

leaving

heles

of

a

_given

area

(up

to

500

rnm2)

to

allow a certain

degree

of air

ieakage

depending

on

the

test

condition.

The

degree

_{of airtightness of}

_the

joint

_{was expressed as}

_Ai

(rnm:lm),

which

is

the

total

area of

the

holes

divided

by

the

height

of

the

joint.

4.2

Equipment

and

test

methods

a}

The

JIS

method

The

use

of

a static

_pressure

box

with a suitable water spraying

device

_is

specified

in

JIS

A

₁₄₁₄

as

a

"Method

of

performance

test

of

panels

for

building

construction:chap.

6.4

Watertightness

test"

[8].

Fig.14

shows

the

apparatus used

in

the

tests

by

JIS

_method.

The

_{same spray system as used}

_for

_the

_spread

pattern

tests

was

installed

in

the

apparatus.

A

_pair

_{of wall}

_panels

_between

_which

the

joint

model

was attached, were

fixed

_{on an opening of}

_the

box,

The

distance

between

the

wall and

the

spray

nozzle

system was changed

depending

on

the

rain

intensity,

and

was

400mm

for

a

intensity

of

480

mmfhr and

750mm

for

240

mmlhr or

less.

N w w L L

rr

T''T?

I'1

.,

Fig.13

s

N

LR

9bcdbHt

NeX'

I N

"XAIR

SEAL

-';S"

ArR SEAL xJ"'

JD[ n JOINT BI JOi"1 _JalNT

Models

of open

drained

joints

used

in

the

weathertightness

tests

compartment

in

the water cotlecting

box)

24

--abgd5 B].

(a,

manytUto.c-'

ad'""x:'

b,

c, " _nfR JOtNTC _JO[NTD

d

and e

denete

the

area corresponding each

...WATERSPRAY."-.s..

/

tt

.t.ttla,

.t.

l s

E..ttta".-/t.".tt.tt

.-ttt.ttt.t.//1/t...=-ttt,ut..-fttt//tt

aAIR

.t.tt.tt

[R T LECTOR

Table2

Test

epenconditions

for

drained

_joints.the

weathertightenesstests of vertical

WAT[R ja/nt JIS methodtest.T.r.

Y.h.o.

d-TURSnypthod w L nri Onn)trtn)tmmiJm)[nv:Fhr](k:e.2][:m)[:rn)tm:ltmxntFnr) tU]{mVs) S[CTION AIR.IIGHT STEEL HOX

L-.ISe.-1

PLAN

Static

pressure

box

used

-ATERJ SUPPLY

a

A]R Agle2H3cD5,10,

-2o

10

--

_.10-s

o,s o- lzo,2qo, ISOO 4BO O,ISO, 240aso

2iaso,

2do2s850･ z4o

gs?ads･

qo aaaO 10

-

O.ISO, 4SO,T50 10

-

450lo

-

4se10

-

4SO 10 O,4SO-10 OISO qs6.is6

li8･

,ss,+3o,

?

±4,,, 120 +4S.+3D. 4,S.12 o120 ,4S 4,e,IZ 1!O +4S 4.B,lg

12o, t4s.,]o.o, o,a.s.

!40

-10,-4S

12 no, "s,,lo,o, o,e

240

-30.-45

Fig.14

m the

JIS

method.

According

to

the

standard, a

fluctuating

pressure

was

employed.

The

period

of

fluctuation

was

twe

secends, with

the

maximum

pressure

kept

at

1,5times

the

average

and

the

minimum

_pTessure

kept

at

O.5times

the

average.

The

joints

were

tested

with various

joint

widths

W

(mm)

or

lap

lengths

L

(mm)

and

degrees

of airtightness

Ai

(mm:!m)

under various combinations of rain

intensities

Ir

(mmlhr)

and average

_pressures

Pa

(kgfmt).

Test

conditons

are

shown

in

summarized

form

in

TabLe

2.

Tests

were

done

twice

for

each

test

condition, each

time

for

5

minutes.

During

the

tests,

the

positions

of water

_penetration

and

their

drainage

tracks

in

the

joint

cavity were recorded.

The

amount of water

collected

in

each compartment of

the

bottom

box

ws measured at

the

end of

the

test.

b)

The

TURS

method

The

rainstorm simulator which

is

described

in

chapter

2

was

fitted

in

a

box

measuring

1.

8

Tn wide,

2.

1

m

high

and

1.

8

m

deep,

as shown

in

Fig.

15.

The

wall

panels

with

the

joint

model at

their

middle were

fixed

on

one

opening

of

the

box,

The

distance

between

the

wall and

the

TURS

nozzle was

kept

at

300

mm.

The

access

door

to

the

box

was

left

::I

A:C[SStLEFT HALLPANEL JOINTHODEL

Fig.15

s[c

DOOR C40UxlOOOHMT['oee

TOPEp4 WnT[R VRiHGIESTS/

;SliPPLT

'/.,/,/,/t///,//t.t,t.t"..t.'

'.tttttttttttt'z't.tttt//t/FnN

iNO'L[

t/･-]l-.1

FLEXIeLEDUCTSTEEL80X 10:ts:6ol:::m" le]:sv!B:Oa

TESTS

BT

JIS

METHOD

[Rt240HMt-R.PA:4DKG]H! JO[NTWIOTH:10MH

.o"'

"･･<･'IEI:Ig,WiTHA,,

-･.

(Al:aSOMM2tHl

a....

-･..

_e-"

.."-o

ALR.T[GHIJOTNTS pLAr"

Test

arrangement

for

weathertightness tests of

joints

by

TURS

apparatus.

Fig16Amountdepth

of

bcde

COMPARTH[NT

of water collected at vanous

Joint

A.

-25-NII-Electronic Library Service

open

during

the

test

to

allow air

flow

occttr

inside

the

box,

instead

of causing static

_pressure.

The

joint

models were

tested

with a

fixed

joint

_{width or}

lap

length

_and

_various

degrees

_{of airtightness}

_Ai

(mrn'1

m), under various combinations

of

rain

intensities

Ir

{mmlhr),

nozzle

deflection

angies

D

<O),

and

wind

speeds

V

(mls).

These

are also shown

in

Table

2.

Test

were

done

twice

for

each

_test

condition,

each

time

for

six minutes.

4.3

Test

resuits

4,3.1

Plain-sided

joints

Fig.

16

shows

the

_,drainage

_pattern

of water

_penetration

in

a

_ptain-sided

joint

_tested

_by

_JIS

method.

When

the

inside

_gap

of

the

joint

was made _airtight,

the

_amount

_of

_penetration

decreased

_gradually

from

front

_to

_{rear of}

_the

joint,

With

increased

air

leakage,

however,

the

_pentration

in

the

rear

_part

increased,

while

that

in

the

front

_part

decreased.

Thus,

the

water

penetration

became

more

evenly

distributed

over

the

whole

depth

of

the

_joint,

Fig.

17

shows

the

re]ationship

between

the

joint

width and

the

total

amount

of

water

_penetration

for

the

same

test

method.

The

_{amount of waterpenetration}

increased

_almost

_in

_proportion

_to

_the

_jointwidth,

_{and was scarcely affectecl}

by

the

airtightness

of

the

joint.

Fig.

I8

shows

the

ratio

of

the

total

amount of

_penetration

to

the

amount

of rain which was supplied

directly

over

the

face

areaof

the

joint.

The

figure

shows

that

the

ratios were

always

smaller

than

1.

o.

This

suggests

that

in

this

test

method, _{no water other}

than

droplets

which

had

directly

passed

through

the

_joint

opening

entered

the

joint.

Fig,

19

shows

the

drainage

_pattern

in

the

same

joint

which was

tested

by

the

TURS

method.

It

is

clear

from

the

figuTe

that

the

_amount

of

water

that

was collected at

the

first

25

rnm

of

the

joint

depth

is

far

larger

_than

that

was measured

in

the

tests

by

the

JIS

method.

The

figure

also shows

that

the

drainage

_pattern

was scarcely

influenced

by

the

airtightness of

the

joint.

Fig.

20

shows

the

effect of wind speed on

penetration.

The

amount of water

_pentration

markedly

increased

as

the

'

wind

became

stronger.

The

ratio of

the

total

amount of water

_pentration

_to

_the

amount of rain which was

supplied

:

leot': so6"x:; 60-(tts"i. ge:ssl !o:ie

tttt

JOi:Ei,:EIH AiR>,

.r

[A//3oo-qso,HH21H}:'

tttt

tttt

r AIR-TIGHT f JD[NTS

.t

_t..,

TESTS Br JIS raETHOD IR/?40MM/HR

PA,4.0KGIHZ

Fig.17

ftu"sdio::

O 10 JO]Nl W]DTH CMH)

Relationship

between

joint

wi

amount of water

_penetlation.

20

dth

and

total

(Joint

A)

Fig.

₁₈

2.e 1.0 u

9

eA[R.TJGHT _JOINTS -JOtNTSWITHAiRLEAKAGE/ TESrSBTJISMETHOD [R:Z40HMIHe PA/40iGJH2 . -

d

v

o

Ratio

of

total

of rainfalt and

(Joint

A}

10 !O GAP NJOTH {NM)

penetration

_{P,)

to

the

preduct

face

area of

the

joint

_(RfA).

:oo:E: ISOg-,:;:

.Y,'

100s:t: se::o T[STS BV TURS H[THOO ]E/12a"HIHR,v:sMis, D:O'JOTNT NrDTH/10HM JOrNTS WTTH A]R LEAKnGEcAT/aSOMH2/M) "/ AtR.TIGHT JOINT

:;.:do::)t2o]:

aoo-!Ims: 200 a

Fig.19

Amount

of of

Joint

A.

bcd

COMPARTMENT water corlected at e various

depth

o r[STS BT TUR5

ilETHOD

Joii.i!2eHMrHR

1/p

fif,,;6R::,:oH"

cgl:,,,,

MENT A TOTAL 5UH OF

/

COMPARTHEHTS

f B TO..E...A

....,....

...-"/..A--""

a

Hg.20

Effect

of

(Joint

A)

4 B 11

WINO SPEED CNis)

wind speed on water

_penetration

-

₂₆

'

1.S

2as

-L -Eo-e.sF(u o

Fig

21

JOINTS AI:150.4SOMM21H CAp WrDTH,10HM TESTS eT J[S M[THOO t[R/240MMiHR.PA/aOKGIM2}

.A..

"A--'"'

'"'''"''"'-･･--･-･･-A

TESTS

BT

TURS HETHeD

CV:BHts.IR/120MHiHR.D/.4S.)

O S 10

HEIGHT OF PROJECTING EOCE tHM)

Ratio

of total

_penetration

in

joints

with

_projecting

side

edges

(P.)

to

that

in

joints

without edges

(

Pts).

oyer

the

face

area of

the

joint

was respectively,

This

means

that,

water on

the

wall surface near

to

move

diagonally

and

flow

into

It

is

also seen

from

Fig.

20,

remained at

the

front

part

of

the

4.3.2

Joints

with

_projecting

Fig.21

shows

the

amount

was

found

between

two

joints.

But

B1-B3

than

in

_joint

A,

Obviously,

from

entering

the

_joint.

10

mm.

The

above

results

effect

of

attaching

such

features

4.3.3

The

labyrinth

joints

Fig,that

most of

the

water

that

ha

the

tests

by

the

TURS

method,

No

measurable method whil

,

the

TURS

mehtod.

the

nozzle

direction.

The

closer

penetration

became.

It

is

also

penetration,

compared with

the

4.4

Discussion

As

far

as

the

amount an

gave

considerably

different

test

apparently

attributed

to

the

fo

the

TURS

:stu-sv::'ts:s:

:;.s:

400 3oo 200 100

Fig.

₂₂

COMPARTME

Arnount

of watei collected

between

labyrinth

_jeints.

NTpenetratlen

the

fins

in

o

x

o; zo

gl

u"'. etU

:E

:m

L: e. ₁₀

!

op･

g:

Q.:

..

E

[a

:z

::.

.4s

o +4i

ui

tlozlLE DEFL[CT]aN ANCLE [')

Fig.

23

Amount

of water

_penetration

beyond

the second

fin

of

labyr{nth

joints

in

relation

to

impingementdirection.

at wind speeds of

O,

4,

8,

and

12

mls,

During

the

tests,

it

was observed

that

forced

the

run-off water

'

entered

the

joint

from

adjacent

surfaces

calculated as

1.1,

2.3,

9.9

and

27.8

by

this

test

method, a

large

part

of

the

water

penetration

is

caused

by

side

flow

of

the

_joint,

especially when

the

wind

is

strong.

sideward air

current

along

the

wall

_panel

which occurs when

the

outlet

is

away

from

the

joint

the

_joint

opening.

however

that

most of

the

water

that

had

i

joinL

edges

of

total

water

_penetration

in

joints

B1,

B2

and

B3

in

the

form

of

their

ratios

to

the

amount

in

ioint

A

having

same

joint

gap.

In

the

tests

by

JIS

method,

little

difference

in

the

amount of

_penetration

,

in

the

tests

by

TVRS,

the

amount

of

penetration

was much smaller

in

joints

the

_projecting

edges at

both

sides of

joints

B

1-B

3

had

some effect

in

preventing

the

side

flow

water

The

height

of

the

edges,

however,

seemed

to

have

little

effect,

at

least

within

heights

of

3

to

also

indicate

that

the

different

test

method may

lead

to

completely

different

evaluation

of

the

to

improve

the

weathertightness of open

drained

joints.

22

shows

the

amount of water which was collected

between

the

fins

of

joints

C

and

D.

It

is

seen

from

the

figure

d

entered

into

the

joint

was

blocked

by

the

first

fin.

The

amount

of water

that

entered

between

the

first

and

second

fin

(catch

in

compartment

b)

of

joint

C

was

larger

in

the

tests

by

the

JIS

method

than

in

amount of water

penetrated

beyond

the

second

fin

in

both

joints

C

and

D

in

the

test

by

the

JIS

e a small amount of water was collected

beyond

the

second

fin

of

both

joints

when

they

were

tested

by

Fig.

23

shows

the

sum of amount of water

that

had

_penetrated

beyond

the

$econd

fin

of

joints

C

and

D

in

relation

to

the

direction

came

to

_parallel

the

_joint

lap,

the

larger

the

amount of water

clear

from

the

figure

that

the

turned

ends

of

the

fins

in

joint

D

largely

reduced

flat

fins

in

joint

C.

d

distribution

of water

that

had

entered

into

the

joints

are

concerned,

the

TURS

method

results

from

the

resuits with

the

JIS

method.

The

reason

for

the

difference

is

11owing

two

characteristics of

the

artificia} rainstorm conditions which are

_provided

by

-27-NII-Electronic Library Service

1)

An

air stream along

the

test

wall which causes a

side

flow

of

run-off

water.

2>

A

wider variation

in

the

movement of water

drops

both

in

velocity and

in

direetion

of

impingement.

According

to

a report on

the

natural exposure

tests

of vertical open

drained

joints,

the

majority

of

water reaching a vertical

joint

flowed

sideways

from

adjacent

surfaces, and

the

amount of water entering

the

joint

was effectively

reduced when

the

side

flow

was

obstructed

by

such

features

as continuous vertical ribs on

both

sides of

the

joint

[

9

]

,

The

test

results

of

joints

A

and

B

1-B

3

by

the

TURS

method clearly showed

the

same

trend

as

the

findings

from

the

natural exposure

test

_described

above,

No

such resemblance was

found

wiht

the

test

results

by

the

JIS

method.

As

for

the

movernent of raindrops near

the

wall surface,

it

has

been

found

_through

a

full

scale measurement of

driving

rain

impaction

on a

high

vise

building,

that

_quite

a

Iarge

_part

of raindrops

hit

the

wall

horizontally

with small

impaction

angles, especially at

places

near

the

corners of

buildings

[10,

11],

The

test

results with

the

labyrinth

joints

show

that

incorporation

of such

features

as

the

direction

and

kinetic

energy of raindrops

is

indispensable

for

test

methods

for

evaluating

the

weathertightness

of

open

drained

joints.

The

JIS

method,

in

which

the

features

defined

for

applying artificial rain are only

the

amount

of water and

its

uniform

distribution

over

the

wall area,

is

liable

to

overestimate

the

rain shielding ability of open

drained

joints,

especially when

they

have

relatively simple

sections.

Static

pressure,

however,

plays

an

important

role

in

_the

movement of water

in

the

joint.

The

_pressure

difference

causes an air

stream

in

the

joint

cavity,

provided

there

is

any airleakage at

the

back

of

the

joint.

If

the

velocity

of

the

air

stream

is

high

enough,

water

which

otherwise

drains

down

the

inner

surface of

the

joint

cavity

is

forced

to

flow

sideways and move

towards

the

rear

_part

of

the

joint

(see

Fig.16)

or

is

torn

off

the

edge of

the

labyrinth

fins.

In

the

tests

by

the

TURS

method,

it

is

not

intended

to

form

any static

_pressure

over

the

test

wall, and

this

may

be

the

reason

why

the

large

amount of water

that

had

flown

into

the

_joint

opening

from

adjacent

sufaces

remained mostly

at

th

front

_part

of

the

joint

and

did

not extened over

the

whole

depth

of

the

joint.

Inclusion

of static

_pressure

in

the

tests

utilizing

the

TURS

apparatus might

_possibly

lead

_to

_the

attainment of more realistic

test

condiitions

for

evaluating

the

_performance

of open

drained

joints.

Such

a

test

method,

however,

should

be

established

based

on

the

close

investigation

of actual exposure conditions of external walls

to

driving

rain.

5.

Conclusions

Both

the

spreading

_pattern

of

raindreps

after

_passing

through

the

joint

opening and

the

manner

ef

rain water

penetration

into

the

cavity of open

drained

joints

differ

considerably

depending

on

the

_test

method

and

the

apparatus used.

The

new rainstoTm simulator

(TURS}

which

had

been

developed

by

the

author was

found

to

_provide

driving

rain

impingeinent

cenditions

that

are close

to

those

over external walls which aTe naturally exposed

_to

driving

rain,

and

this

is

mainly

because:

(

1

)

it

can

_provide

a wide range of variety

in

conditions

of

raindrop

impaction,

both

in

dire

¢

tion

and

kinetic

energy.

(2)

it

can cause side

flow

of

run-off water on

the

test

wall,

The

static

_pressure

box

method, which

is

widely used as astandard method

fer

testing

weathertighness of external wall units

is

not satisfactory

for

evaluating

the

_perfromance

of open

drained

joints.

Further

tests

are

in

progress

with

different

types

of

joints

in

order

to

investigate

the

applicability of

the

apparatus,

as

well as

to

collect

knowledge

for

improving

the

design

of open

drained

joints.

Acknowledgement$

This

study

was

partly

supported

by

the

Grant-in-Aid

for

Scientific

Research

from

The

Ministry

of

Education

of

Japan

in

1980

and

1981.

The

author wishes

to

express

his

thanks

to

many of

the

fermerstudents

of

the

Department

he

belongs,

especially

to

Messrs.

M,

_Ohgiya,

_H.

_Oshikawa,

_T.

_Uehara,

_S,

_Itoh,

_Y.

_Katsuki,

N.

Arisawa,

T.

Kawaharada,

A.

Watanabe,

K.

Kuno,

K.

Iida,

and

Y.

Yamada

for

their

valuable assistance

to

the

experimental

works.

Reterences

O

Specification

for

performance

testing

of rnetal curtain walls;Test

to

determine

water

infiltration

at roorn

temperature

by

dynamic

pressure,

National

Assec.

of

Architectural

Metal

ManufactuTeTs,

1962.

Chicago.

2)

3}

4}

5)

6)

7}8}

9)

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11}

IZ}

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E,

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1985,

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74-79.Itoh

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Annuai

rneeting of

Architectuial

Inst.

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T.

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A.

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H.

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RainstoTm

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weathertightness of exteinal vvalls

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in

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Annual

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Architectural

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1981

{Materials

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395-396.

Herbert

M.R.M.

:

Open

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rain screen claddings,

BRE

current

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1974.

Japanese

Industrial

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D.,

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C.J.D.

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M.R.M.

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paper64c

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H.

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Driving

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Summaries

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1984.

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Spreading

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