THERMAL INSULATION
REQUIREMENTS FOR
MANHOLE DESIGN
Kathie Leonard
Auburn Manufacturing, Inc.
and
Gordon Hart, P.E.
Artek Engineering, LLC
IDEA Annual Conference
Indianapolis, Indiana
June 15, 2010
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PRESENTATION GOAL:
Address the Need for
Thermal Insulation
in Manholes
A Fact Finding Session
2
WHYWE ARE HERE
• Manufacturer (AMI) and Consultant (ARTEK)
on Insulation Systems
• Demonstration Projects
• IDEA Steam Distribution Workshop –
Reno 2/ 10
WHYYOU ARE HERE
• To provide feedback on applications and
performance requirement of manhole
insulation needs.
3
Why is Thermal Insulation
Needed in Manholes?
In other words…what
made us realize that we
need to address this
subject, anyway?
4
Why is Thermal Insulation
Needed in Manholes?
• Piping and piping
components found
beneath manholes
• The manhole covers
themselves
5
What is Unusual About the
Manhole Environment?
•
•
•
•
•
Confined space
Sometimes floods
Frequently very humid
Experience steam leaks
Difficult to insulate piping
components
• Cramped working conditions
6
Why Do We Care About the
Manhole Environment?
• Manhole covers can pose a
health & safety problem if
overheated
• Maintenance personnel need to
enter manholes
• As ‘confined spaces’ manholes
can pose safety concerns for
maintenance personnel
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List of Insulation Exposure
Requirements
•
•
•
•
•
•
•
•
Continuous 415°F steam service
temperature
Submergence under water
Steam environment ( hot, high
humidity – 300°F, 100% RH)
Sometimes cool, high humidity
environment
Dripping water
Dripping oil from road surfaces
Road salt and other corrosive
chemicals
Some physical abuse
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Insulation System Options –
Piping Components
•
Rigid, preformed insulation
(fiber glass, mineral wool, perlite,
calcium silicate, cellular glass, etc.)
•
Flexible blankets
(fiber glass batts, glass fiber mats,
HT fiber mats, aerogel mats, flexible
elastomeric sheet.)
•
Pre-engineered removable/ reusable
blankets with coated fabric
•
Site-cut removable/ reusable
modularized blankets with coated
fabric
9
Insulation System Options –
Piping Components
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Insulation System Options –
Piping Components
Fiber glass pipe insulation with ASJ
Calcium silicate pipe & block insulation
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Insulation System Options –
Piping Components
Preformed rigid pipe insulation with metal jacketing
(calcium silicate with aluminum jacketing)
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Insulation System Options –
Piping Components
Preformed rigid pipe insulation with
metal jacket
Source:
National Commercial &
Industrial Insulation Standards
Manual-MICA
Plate #12
13
Insulation System Options –
Piping Components
Fiber glass elbows with
PVC or metal jacket
Source:
National Commercial &
Industrial Insulation Standards
Manual-MICA
Plate #12
14
Insulation System Options –
Piping Components
Calcium silicate pipe & block insulation (rigid)
15
Insulation System Options –
Piping Components
Flexible elastomeric sheet
16
Insulation System Options –
Piping Components
Flexible elastomeric sheet covered with lagging
cloth and a vapor retarder mastic
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Insulation System Options –
Piping Components
Fiber glass pipe and tank wrap
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Insulation System Options –
Piping Components
Flexible aerogel insulation
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Insulation System Options –
Piping Components
Pre-engineered removable/ reusable
insulation blankets
National Commercial & Industrial
Insulation Standards Manual-MICA
Plate #47
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Insulation System Options –
Piping Components
Pre-engineered removable/ reusable
insulation blankets
21
Insulation System Options –
Piping Components
Removable/ reusable modular insulation.
Measured and cut from rolls at the job site.
Photo Courtesy:
EverGreen®Cut n’ Wrap
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Insulation System Options –
Piping Components
Removable/ reusable modular insulation.
Cut from rolls at the job site.
Attached with hook and loop fastener strapping
Photo Courtesy:
EverGreen®Cut n’ Wrap
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Insulation System Options –
Piping Components
Multi-ply laminate jacketing over preformed
rigid pipe insulation
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Insulating Manhole Covers
Objective:
To keep the covers from becoming
sufficiently hot to burn people
Method:
To prevent the cover’s external
temperature from exceeding
130°F (excluding the effects of
sunlight)
Concern:
Steam leaks within the manhole
and conduction heat losses from
bare pipe components
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Insulating Manhole Covers
Environmental Conditions:
Manhole ambient temperature of
at least X°F and outdoor ambient
temperature of Y°F with a wind
speed of Z mph.
Problem:
If we know the values of X, Y, and
Z, then we can solve the heat
transfer problem and determine
the minimum thickness of
insulation required for a given
type of insulation.
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Insulating Manhole Covers
General Insulation
System Requirements
•
•
•
•
Keep out steam & water
Maintain thickness
Be durable
Either remain attached to
cover or be detachable
• Other?
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Insulating Manhole Covers
Results of Heat Transfer Calculation
3E Plus®
•
•
•
Manhole temp = 300°F
Ambient conditions of 90°F, 0
mph wind
Insulation type: glass fiber felt
(ASTM C1086)
•
Cover: Zero permeance multi-ply
laminate with an emittance = 0.0
•
Solution: Required thickness to
keep temp < 130°F = 1.0 inch
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Insulating Manhole Covers
Questions
•
Are these assumed conditions
reasonable?
•
What other design parameters
should be considered for manhole
cover insulation?
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What Might the Insulation
System Requirements Be?
•
Either to remain dry at all times or
be able to dry without damage
•
To maintain thickness
•
To cover all pipe components
(exclude valve wheels)
•
To exclude water vapor & liquids
•
To be removable/ reusable on
valves, flanges, & other such
components
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Manhole Piping Insulation
Systems
Questions
•
Is this a complete list of insulation
system requirements for manhole
piping?
•
Is this a complete list of insulation
material solutions?
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THERMAL INSULATION
REQUIREMENTS FOR
MANHOLE DESIGN
Thank you…
Visit us at AMI at Booth #34
Contacts:
[email protected]
[email protected]
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