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Salt, Dust and RHSalt, Dust and RHRisks in Coastal and Inland AreasRisks in Coastal and Inland Areas
David ThickettDavid Thickett
Collections Management Collections Management TeamTeam
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29/1
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19/1
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10/1
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31/1
2/20
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21/0
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11/0
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04/0
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25/0
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15/0
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27/0
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17/0
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29/0
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19/0
8/20
04
Tem
per
atu
re in
°C
0102030405060708090100
Rel
ativ
e H
um
idit
y in
%
Telephone ExchangeTelephone Exchange
TelephonTelephonee
RepeaterRepeater
% surface coverage% surface coverage 1414 8181
weight loss weight loss ((mg/cmmg/cm22))
0.10.1 0.90.9
0
2
4
6
8
10
12co
vera
ge /
# pa
rticl
es (%
/ x1
00)
% coverage
# particles
0
50
100
150
200
250
sodium magnesium sulphate chloride
Ion
Dep
osit
ion
Rat
e (µ
g/m
2 /day
)
TelephoneRepeater
Airborne DustAirborne Dust
0100020003000400050006000700080009000
10000
1.00 1.50 2.00 2.50 3.00
time (days)
# p
arti
cles
>0.75μm
>1.0μm
>2.0μm
>3.5μm
>5.0μm
>7.5μm
>10.0μm
>15.0μm
Surface wetness sensorSurface wetness sensor
Surface wetness resultsSurface wetness results
Critical RH = 53%
Repeater = 50%
0
10
20
30
40
50
60
70
80
13/02/200400:00
04/03/200400:00
24/03/200400:00
13/04/200400:00
03/05/200400:00
23/05/200400:00
date
T/R
H (
°C/%
)
0
500000
1000000
1500000
2000000
2500000
3000000
resi
stan
ce (
Ω)
temp
RH
resistance
40 45 50 55 60 65 70 75 80 85 90
clean
XP
salt
salt+XP
RH (%)
54
63
78
81
ShieldShield UntreatedUntreated
TelephoneTelephone 0.001 (99.0%)0.001 (99.0%) 0.1060.106
RepeaterRepeater 0.018 (98.1%)0.018 (98.1%) 0.9340.934
Environment Under TyvekEnvironment Under Tyvek
0
20
40
60
80
100
22/06/200400:00
12/07/200400:00
01/08/200400:00
21/08/200400:00
10/09/200400:00
RH
(%)
0
5
10
15
20
25
30
Tem
pera
ture
(ºC
)
Room RH Tyvek RH
Tyvek T
0
500000
1000000
1500000
2000000
2500000
3000000
15/09/200400:00
20/09/200400:00
25/09/200400:00
30/09/200400:00
05/10/200400:00
10/10/200400:00
15/10/200400:00
20/10/200400:00
Re
sis
tan
ce
(Ω
)<
We
t
D
ry > Tyvek
Desk
0
50
100
150
200
250
300
350
(µg/
m2 /d
ay)
inner case 1 case 2 outer case 3
Chloride Deposition RateChloride Deposition Rate(30 days)(30 days)
(µg/
m2 /
day)
Case Fabric Chloride Case Fabric Chloride
0
20
40
60
80
100
120
140
chlo
rid
e (μ
g)
case 1 case 2 case 3
-40 -20 0 20 40 60 80 100
geothiteakaganeitemagnetiteiron
2.12%[Cl] = 0.19%
FeO0.833(OH)1.167Cl0.167 ~ 6.9%ClStahl, Corr. Sci, 2003
β-FeOOH6-12%Cl —> α-FeOOH<0.7%Cl
Thickett, proceedings of IRUG6, in press
Surface AnalysisSurface Analysissilver coupons 30 dayssilver coupons 30 days
00.05
0.10.15
0.20.25
0.30.35
0.40.45
Fashio
n
Death
Roman
Guy'
s
18th
Cen
tury
amou
nt %
0
0.5
1
1.5
2
2.5
incr
ease
in b
*
sulphidechloride
Thickett, Hallett, Bradley and LeeHildesheim, in press
Chloride SourcesChloride Sources
GaseousGaseous DustDust HandlingHandling UseUse Conservation TreatmentsConservation Treatments Post excavation cleaning (coins)Post excavation cleaning (coins)
Anion Deposition RateAnion Deposition Rate
0
20
40
60
80
100
120
140
160
180
fashion death Roman Guy's 18thCentury
case
ion
de
po
sit
ion
ra
te
(ug
/m2/d
ay
)
chloride
sulphate
0
10
20
30
40
50
60
0 0.5 1 1.5 2 2.5
AER (/day)
Am
ount
of
Dus
t In
gres
sing
(%
)
Werner Collection Cases Werner Collection Cases at Ranger’s House at Ranger’s House
y = -0.31x + 8.6582
7.2
7.4
7.6
7.8
8
8.2
8.4
8.6
8.8
0 1 2 3
days
ln [
CO
2 p
pm
]
0
0.5
1
1.5
2
Inst
anta
neous
AER
(day-1
)
AcknowledgementsAcknowledgements
University College London University College London Centre for Sustainable Heritage (Bartlett Centre for Sustainable Heritage (Bartlett
School of Architecture)School of Architecture) Department of GeologyDepartment of Geology
Royal Historic PalacesRoyal Historic Palaces Museum of LondonMuseum of London
