<s>
A	O
rack	B-Application
rail	I-Application
,	O
or	O
rack	O
strip	O
,	O
is	O
used	O
to	O
mount	O
rackable	O
electronic	O
hardware	O
and	O
19-inch	B-Application
rack	I-Application
mount	O
accessories	O
within	O
a	O
19-inch	B-Application
rack	I-Application
.	O
</s>
<s>
Within	O
a	O
rack	O
a	O
minimum	O
of	O
two	O
rack	B-Application
rails	I-Application
are	O
required	O
to	O
mount	O
equipment	O
.	O
</s>
<s>
The	O
height	O
of	O
rack	B-Application
rail	I-Application
is	O
determined	O
by	O
the	O
number	O
of	O
rack	O
units	O
required	O
for	O
mounting	O
the	O
equipment	O
.	O
</s>
<s>
The	O
design	O
of	O
racks	O
and	O
rack	B-Application
rails	I-Application
is	O
specified	O
in	O
ECIA	O
-	O
EIA/ECA	O
-310	O
.	O
</s>
<s>
Most	O
rack	B-Application
rail	I-Application
is	O
in	O
sizes	O
from	O
2	O
units	O
high	O
(	O
)	O
to	O
54	O
units	O
high	O
(	O
)	O
.	O
</s>
<s>
Rack	B-Application
Rail	I-Application
comes	O
in	O
two	O
different	O
commonly	O
used	O
forms	O
.	O
</s>
<s>
Tapped/threaded	O
rack	B-Application
rail	I-Application
has	O
round	O
holes	O
tapped	O
for	O
10-32	O
UNF	O
or	O
10-24	O
UNC	O
screws	O
.	O
</s>
<s>
The	O
other	O
common	O
form	O
of	O
rack	B-Application
rail	I-Application
is	O
square	O
hole	O
rack	O
strip	O
which	O
has	O
square	O
holes	O
for	O
captive	O
nuts	O
,	O
available	O
tapped	O
for	O
various	O
different	O
screw	O
threads	O
,	O
that	O
are	O
clipped	O
into	O
the	O
holes	O
as	O
needed	O
to	O
mount	O
equipment	O
.	O
</s>
<s>
In	O
both	O
cases	O
,	O
rack	O
screws	O
and	O
washers	O
are	O
required	O
to	O
mount	O
rack	B-Application
mount	I-Application
equipment	O
to	O
the	O
rack	B-Application
rail	I-Application
.	O
</s>
<s>
The	O
size	O
and	O
strength	O
of	O
rack	B-Application
rail	I-Application
is	O
determined	O
by	O
its	O
application	O
.	O
</s>
<s>
Increased	O
thickness	O
of	O
steel	O
results	O
in	O
stronger	O
rack	B-Application
rail	I-Application
and	O
varieties	O
of	O
rack	B-Application
rail	I-Application
can	O
be	O
found	O
such	O
as	O
double	O
angle	O
and	O
single	O
angle	O
rack	B-Application
rail	I-Application
.	O
</s>
