27.04.2013 Views

Figure I Generalized map of the Wilbur Mining ... - University of Utah

Figure I Generalized map of the Wilbur Mining ... - University of Utah

Figure I Generalized map of the Wilbur Mining ... - University of Utah

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

The' following four^ types <strong>of</strong> piping systems<br />

were investigated:<br />

- Steel Pipe in a Concrete Tunnel (350°F Maxiraura<br />

Temperature). This type systera is essentially<br />

a poured-iri-place or precast reinforced concrete<br />

tunnel with removable'concrete lids, which ca'h be<br />

used for sidewalks, and renraved to provide access<br />

for maintenance or insiiallation <strong>of</strong> future p.ipeS;.<br />

The insulated carrier pipes'are supported on steel<br />

rollers which are imbedded into <strong>the</strong> concrete tunnel,<br />

hfter installation, piges are insulated with<br />

preformed fiberglass or rPckwool. Allowance for<br />

expansion is by\a bellows type expansion .joint<br />

which is dual acting with an anchor.between <strong>the</strong> bel-<br />

1 ows. The pipe is al so free to expand at elbows<br />

with <strong>the</strong> use <strong>of</strong> guides. The concrete tunnel is<br />

placed on a gravel bed which contains a dizain tile.<br />

The concrete tunnel is extremely durable, can be<br />

used for o<strong>the</strong>r utilities, arid can be; constructed by<br />

local contractors. Its main drawbaek is that it is<br />

expensive to .construct compai-ed to o<strong>the</strong>r type systems<br />

.<br />

Concrete tunnel type pi pi rig is popular in<br />

European district'heating systeras and <strong>the</strong> Icelanders<br />

who usually use it for pipes larger than 10 inches,<br />

in diameter, -claim <strong>the</strong>re is no better system.<br />

CONCBETE TFffiNirf)<br />

INSULATION<br />

sreeL PIPE<br />

ROLLER PW)<br />

'BACKfiLL<br />

GBAVEL BED<br />

FIGURE 5. Steel Pipe in a Concrete Tunnel<br />

Steel Pipe in a Protective Co.verinn ,(25D°F<br />

Maximum Temperature).- A single carrier pipe- is enclosed<br />

in polyurethah irsulation with a. tight jacket<br />

<strong>of</strong> glassfiber reinforced piasti'c (FRP) <strong>of</strong> PVC.,<br />

Joints <strong>of</strong> pipe are welded, insulated, and sealed<br />

with a joint kit and placgd in a bed <strong>of</strong> sand in <strong>the</strong><br />

CLASS 8 BED<br />

FRP JAGKET<br />

URETHANE INSULATION<br />

STEEL RIPE<br />

FIGURE 6. Steel Pipe in a Protective Covering<br />

trench. Manholes are constructed between anchor's<br />

to house <strong>the</strong>! expansion bel Vows and insulation<br />

around elbows is oversized to allow expansiori.<br />

There are usually eight segments (320. ft) between<br />

an anchor and manhole, <strong>the</strong> manholes are construeted<strong>of</strong><br />

reinforced concrete; with drain provisions, this<br />

type system is very durable, r^esistant to external<br />

corrosion^ however, susceptible to exterior cdrro-<br />

391<br />

Lund j et. al.<br />

sion. Although costs per lineal foot are comparableto<br />

rion-TCtallic pipe, <strong>the</strong> added cost for manholes<br />

arid expansion bellows makes it more expensive.<br />

Fiberglass Reinforced Plastic Pipe (FRP)<br />

(.210°F Maximum temperatureT^ A .single: FRP carrier<br />

pipe is enclosed in polyurethane insulation with a<br />

tight jacket <strong>of</strong> FRP or PVC. The pipe is a filament<br />

wound fiberglass with ei<strong>the</strong>r epOxy or polyester<br />

resin plastic. The epoxy type can handle<br />

temperatures up to 350°F 'a'nd has a low coefficient<br />

<strong>of</strong> roughness, C = 140. The pipe, usually does not<br />

have any expansion joints,, as <strong>the</strong> co.efficient <strong>of</strong><br />

linear expansion is 8.5 x 10^^ per °F as corapared<br />

to 12 X., 10"^ per °F I'or steel pipe. Elbow_s are located<br />

in poured concrete thrust blocks in Order to<br />

hold <strong>the</strong> pipe in, position and allpw expansion in<br />

straight lengths. A polyester resin pipe <strong>of</strong> this<br />

type failed recently when it pulled apart, raairily<br />

,a;t joints, when <strong>the</strong> pipe cooled. There is available<br />

pn <strong>the</strong> market a slip-ring type joint.tha't may<br />

be more desirable than <strong>the</strong> epoxy jpiried pipes. A<br />

check On <strong>the</strong> filament wound epoxy resin pipe installation,<br />

carrying .353°F'water", proved satisfactory,<br />

hov/ever, flashing must never occur in FRP<br />

pipe. In areas wHer^e flashing conditions' are expected,<br />

steel pipe sections must be used. The main<br />

'advantages <strong>of</strong> this type piping systera is its resistance<br />

to corrosion and Tow roughness coefficient.<br />

BACKFILL<br />

FIGURE 7\ Insulated FRP Pipe<br />

CLASS B BE13<br />

PVC JACKET<br />

URETKANE INSULATION<br />

FRP PIPE<br />

Asbestos Cement Pipe (AC) (200°F Maximum<br />

Teraperature). This type.pipe has ^an epcfxy 'lined<br />

AC 'carrier' pipe, polyurethane insulation arid an AC<br />

•^^^

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!