Utilities Infrastructure Heating Distributio - APPA · Utilities Infrastructure Heating Distribution APPA Institute for Facilities Management Dallas Jan 2017 ... estimate of required

APPA Institute – Session 301C EU © GLHN Architects & Engineers,Inc.

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Utilities InfrastructureHeating Distribution

APPA Institute for

Facilities Management

Dallas Jan 2017

Bill Nelson PE

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Purpose of Today’s Presentation

• To share information about currenttechnologies related to central plants

• To provide some useful handoutmaterial with sizing guides

• To provide a broad understanding ofcentral heating distribution systems

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Agenda

• Introduction

Steam Piping System

Radial vs looped

Hot Water Piping

Reverse Return


Design and OperationalIssues

–Heating Media

•Steam

•Hot Water

Steam Systems

–High Press – over 350 psig

–Med Press – 15 to 350 psig

–Low Press – up to 15 psig

Hot Water Systems

–High Temp – over 350 ° F

–Medium Temp – 250 to 350 ° F

–Low Temp – under 250 ° F


Velocity Limits

–Steam 7500 fpm

–Hot water 8 fps (500fpm)

Design Issues

– Thermal Expansion

(anchors, expansion control, pipe guides)

– Insulation (factory applied, field applied)

– Access for Maint and Repair

– Safety

Design Issues

–Building Connections

• Steam

PRV, convertors, traps, meters

• Hot Water

Control valves, pumps, meters


System Architecture

–Radial vs. Looped

–Radial – from plant to load

–Loop – from plant to load & back

Radial vs Looped

–Radial

limited flexibility for expansion

–Loop

ability to expand

easy to isolate

higher cost

more planning required

Radial Piping System


Looped Pipe System

Types of DistributionSystems

–Direct Bury (Boring)

–Utilidors

–Tunnels

Direct Bury Utility Systems

–Poured in place insulation

–Pre-insulated pipe (HDPE)

–Lowest first cost

–Easy installation

–Expansion loops

–Access Vaults


Pipe Boring

–At times the best alternative

–Can be expensive

–Requires excavations at both ends

–Limited flexibility

Utilities Typically Buried

– Steam and Hot Water

– Chilled Water

– Water, Nat Gas, Sewers

– Primary Electrical

HDPE pre-insulated pipe

• Steam or Hot Water Direct Bury


Direct Bury Piping Detail

Trench Detail

Pipe Anchor


Wall Penetration

Large Direct Bury Project

Expansion Loop


Expansion Joint (winter)

Utilidors

–Shallow covered structure

–Accessible and non-accessible top

–One option -

poured slab with pre-cast top

–More protection and life than bury

–Less costly than tunnels

Utilidor Diagram


Utilidor Design

Pre-Cast Utilidor

Winter time Utilidor


Tunnels

–Big and deep enough to walk in

(some crawl tunnels)

–Tops often sidewalks

–Long Life (50 + years)

–Maximum access

–Greatest flexibility for expansion

–Highest Cost

Tunnels

–Poured in place concrete

–Pre-manufactured

–Typically utilities on one side

–Ventilation

–Lighting & power

–Drains

–Highest first cost

Box Style Tunnel


Box Style Tunnel

Arch Style Tunnel

Arch Style Tunnel


Pre-Manufactured Tunnel

Operation and MaintenanceIssues

– Vaults & manholes (bury & utilidor)

– Structure, joints, seals (utilidors &tunnels)

– Steam

traps, pumps, PRV’s, valves, insulation

– Hot Water

valves, pump seals, insulation

Utility Vault


Pre-Cast Utilidor

• Steam Traps

• Insulation

• Flash Tank

Expansion Joint


Expansion Joint and Anchor

Cost of Construction

–First Cost vs. Life Cycle Cost

–Expandability

–Long Term Reliability

Direct Bury

–Welded pipe for low temp Hot Water

$500 + per foot

–Welded pipe for high temp Hot Water

$700 + per foot

–Welded pipe for Steam

$800 + per foot

–Boring – get estimates


Utilidors

–$2000 to $3000 per ft

–Common size is 5 ft W by 3 ft deep

Tunnels

–$4000 to $7000 per ft

–Common size is 8 ft W by 8 ft H

–But will last 100+ years

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HVAC System:Steam and Condensate

• General Arrangement

Boiler Feed Pumps Condensate Pumps

Deaerator

Condensate Tank

Boiler

Building


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Steam Piping Design• Distribution System Types

• Walking Tunnel

• Shallow Tunnel

• Direct Buried

• Material Types

• Carbon Steel (ANSI B 16.9 A106)

• Other

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Piping Design• Insulation Types

• Factory applied (Perma Pipe)

• Field applied

• Pitch

• Velocity/pressure limits

• Condensate Returns/Trapping

• Effect of Leaks

• Expansion devices

• Supports/guides/anchors

• Hookups/Accessories


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Condensate Return-Traps• Typical Application

• Types

• Thermostatic

• Liquid expansion

• Balanced pressure

• Bimetallic

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Condensate Return-Traps• Types (cont’d)

• Mechanical

• Bucket

• Float

• Thermodynamic

• Impulse

• Disc

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Typical Application


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Mechanical-Float & Thermostatic

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Expansion-Basic Restraint

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Expansion-Sliding Joint


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Expansion-Bellows

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Hookup-Main Drips

Bad

Good

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Hookup-Takeoff


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Waterhammer-Steam Induced

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Tunnel Flooding-Condensate Generation

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STEAM SYSTEM PIPING CAPACITY 1000 lb/hr(1000 ft2)

[HP]

Steam QuantityAreaFeedwater Pump HP

This chart is intended to be used for obtaining an initialestimate of required pipe size and cost. Actual systemdesign must be based on values obtained specifically forthe project. Total installed cost per linear ft. of buriedsupply & return (2 pipes) piping. Price includes trenching,insulation, fittings, backfill & moderate amounts ofsurfacing repairs. For total project cost add A-E fees,testing, escalations, contingencies, etc.

Building SQFT values are based on 60 Btuh/sqft peakaverage combined load (building heat and domestichot water). For winter lows below +25 F: at 0 Fmultiply building SQFT by 0.8, at -20 F multiply buildingSQFT by 0.6.

Steam lines are sized to approximately 10,000 ft/min.

Condensate lines are sized to approximately yieldpressure drops less than 2’/100’.

Prices shown are construction cost for a direct burieddual conduit piping system.


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Utilities Infrastructure Heating Distributio - APPA · Utilities Infrastructure Heating Distribution APPA Institute for Facilities Management Dallas Jan 2017 ... estimate of required