9
TABLE 1
Product
EN 124
Group
Recommended minimum Cover
Class
*
Maximum Chamber
Depth (mm)
Exca
va
tion Footprint
Base Material
Bracing
Backfill
Additional Information.
1A
15
120
01
00
mm
or width of com
pacting equipm
en
t5
0m
m
of com
pacted stone (MOT
1)
Co
mp
acted MO
T1
stone, or as dug
ma
terial if of a g
ranular t
yp
e.
2B
12
5
120
01
00
mm
or width of com
pacting equipm
en
t1
00
mm
of co
mp
acted stone (MOT
1)
Co
mp
acted MO
T1
stone or lean
mi
x concrete
.
3
C250
120
01
50
mm
or width of com
pacting equipm
en
t1
50
mm
of lean
mi
x concrete (C40)
Mini
mu
m
150m
m
C40 concrete
4
D400
200
02
00
mm
or width of com
pacting equipm
en
t
150m
m
of lean
mi
x concrete (C40),
reinforced w
ith
A393
me
sh
.
Mini
mu
m
200m
m
C40 concrete
1A
15
120
01
00
mm
or width of com
pacting equipm
en
t5
0m
m
of com
pacted stone (MOT
1)
2B
125
120
01
00
mm
or width of com
pacting equipm
en
t1
00
mm
of co
mp
acted stone (MOT
1)
3
C250
120
01
50
mm
or width of com
pacting equipm
en
t1
50
mm
of lean
mi
x concrete (C40)
Mini
mu
m
150m
m
C40 concrete
4
D400
200
02
00
mm
or width of com
pacting equipm
en
t
150m
m
of lean
mi
x concrete (C40),
reinforced w
ith
A393
me
sh
.
Mini
mu
m
200m
m
C40 concrete
1A
15
240
01
50
mm
or width of com
pacting equipm
en
t5
0m
m
of com
pacted stone (MOT
1)
Sidewall length < 1500m
m
As dug i
f gran
ular is ok
, otherw
ise co
mp
acted MO
T1
stone.
Sidewall length between 1500 and 2500
mm
com
pacted MOT
1 stone.
Sidewall length > 2500m
m
mi
ni
mu
m
150m
m
C40 Concrete
2B
125
240
01
50
mm
or width of com
pacting equipm
en
t1
00
mm
of co
mp
acted stone (MOT
1)
Sidewall length < 2500m
m
co
mp
acted MO
T1
stone
Sidewall length > 2500m
m
mi
ni
mu
m
150m
m
C40 concrete
3
C250
240
01
50
mm
or width of com
pacting equipm
en
t1
50
mm
of lean
mi
x concrete (C40)
Sidewall length < 2500m
m
co
mp
acted MO
T1
stone
Sidewall length > 2500
mm
m
inim
um
150
mm
C40 concret
e
4
D400
2400
200m
m
or width of co
mp
acting equip
me
nt
150m
m
of lean m
ix concrete (C40),
reinforced w
ith A393 m
esh.
Mini
mu
m
200m
m
C40 concrete
5E
600
240
02
00
mm
or
width o
f co
mp
acting equip
me
nt
250m
m
of lean
mi
x concrete (C40),
reinforced w
ith 2 lay
ers A393
me
sh
equall
y
spaced
.
Mini
mu
m
250m
m
C40 concrete
1A
15
120
01
00
mm
or width of com
pacting equipm
en
t5
0m
m
of co
mp
acted stone (MOT
1)
Bracing required on
cham
bers w
ith side wall
Co
mp
acted MO
T1
stone, or as dug
ma
terial if of a granular t
yp
e.
2B
12
5
120
01
00
mm
or width of com
pacting equipm
en
t1
00
mm
of co
mp
acted stone (MO
T1
)
Bracing required on
cham
bers w
ith side wall
lengths greater than
600m
m.
Co
mp
acted MO
T1
stone or lean
mi
x concrete.
3
C250
120
01
50
mm
or width of com
pacting equipm
en
t1
50
mm
of lean
mi
x concrete (C40)
Bracing required on
cham
bers w
ith side wall
lengths greater than
600m
m.
Mini
mu
m
150m
m
C40 concrete
4
D400
200
02
00
mm
or width of com
pacting equipm
en
t
150m
m
of lean
mi
x concrete (C40),
reinforced w
ith A393 m
esh.
Bracing required on
cham
bers w
ith side wall
lengths greater than
600m
m.
Mini
mu
m
200m
m
C40 concrete
1A
15
200
01
00
mm
or width of com
pacting equipm
en
t5
0m
m
of com
pacted stone (MOT
1)
No requirem
ent for
bracing.
Co
mp
acted MO
T1
stone
2B
125
200
01
00
mm
or width of com
pacting equipm
en
t1
00
mm
of co
mp
acted stone (MOT
1)
No requirem
ent for
bracing.
Co
mp
acted MO
T1
stone or in areas w
here additional stabilit
y
is required lean m
ix
concrete can be used.
3
C250
200
01
50
mm
or width of com
pacting equipm
en
t1
50
mm
of lean
mi
x concrete (C40)
No requirem
ent for
bracing.
Mini
mu
m
150m
m
C40 concrete
4
D400
200
02
00
mm
or width of com
pacting equipm
en
t
150m
m
of lean
mi
x concrete (C40),
reinforced w
ith
A393
me
sh
.
No requirem
ent for
bracing.
Mini
mu
m
200m
m
C40 concrete
Double bracing, equall
y
spaced
mm
single central
bracing, required in both
directions
.
mm
double
bracing at equal
spacing.
mm
bracing at
600m
m
spacing using
acro
w
props, both
hori
zo
ntall
y
and vertical
ly
.
Mini
mu
m
100m
m
C40 concrete
*Cover Class,
refers to recommended mini
mum frame & cover for EN124 Group, backfill r
equirements are as per EN124 Group, see diagram xxx for referenc
e
Footw
ay
Fortress
Carriagew
ay
Fortres
s
M
odula (Sidew
all
upto 1200mm)
Modula (Sidew
all
grea
ter 1200mm)
Ultima
Hy
drant Sections
require onl
y
a
granular bac
kf
ill. Final adjustm
ent is
not necessar
y,
25m
m
sections
available. Split base/dog
ke
nnel
arrangm
ent around infrastructure.
TS
SL
base section do not require to
be concreted,
mi
ni
mu
m
depth of
450m
m
upto 900
mm
French
Te
lecom
SN
C
F
Mo
to
rw
ay
Communications
approved, total s
ys
te
m
available fro
m
su
mp
base, brack
etry
and cover.
Bracing required on
cham
bers w
ith side wal
l
lengths greater than
600m
m.
It is key to note that the chamber backfill conditions relate to where the chamber is installed (EN124 Group).
Example
- If an UL
TIMA
Chamber 1310 x 850 x 1050 deep is to be installed in the footpath (Group 2) but
with a D400 Ductile iron frame and cover.
This should be installed as a group 2 Chamber i.e. base - 100mm
compacted MOT
TYPE 1, backfill - 150mm compacted MOT
T
ype1.
