electrical design reviews - bcxa building commission ... · pdf fileelectrical design reviews...

Don ZerripSenior ConsultantCxGBS®

Electrical Design Reviews

AIA Quality Assurance

Portland Energy Conservation, Inc is a registered provider with The American Institute of Architects Continuing Education Systems. Credit earned on completion of this program will be reported to CES Records for AIA members. Certificates of Completion for non-AIA members are available on request.

This program is registered with the AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.

Learning Objectives

1. Why perform electrical design reviews.2. Review successful tools used to perform electrical

design reviews.3. Where does the design review fit in the commissioning

process.4. Using an example, understand successful methods used

and detail needed to perform a review.5. Results and issues noted in a sampling of electrical

design reviews performed.

AIA Quality Assurance


Why commission the electrical design?•

Design shortcomings can easily be corrected at the design stage

•

It is only “paper”

at the design stage•

Minimal cost when discovered early

•

Reduces risk across the board•

There are indications of mistakes being made at the design stage


Not doing electrical design reviews?•

Yields construction by design and not by intent

•

Errors that exist might be corrected in the field•

There could be the long term results on○Safety○Efficiency○Cost


Goals•

Increase Quality and Safety

•

Reduce Risk•

Minimize Change Orders

•

Increase Reliability, MTBF•

Decrease MTTR

•

Check Drawings Against Project Objectives


Comments•

This is not a code review but rather as the commissioning agent you are a third party working as an independent advocate of the building owner.


The reviewer:•

Should have significant design and hands-on experience in construction, installation, and maintenance of buildings and equipment.

•

Provides another set of experienced eyes reviewing drawings for feasibility, consistency, and completeness.


Tools•

Drawings and specifications○The appropriate set for the task (SD, DD, CD)○You need all of the drawings (A, M, E, ...○Prefer electronic (“pdf”

format)

- Good quality (usually not a problem)- Sequential sheets in one PDF file

○Paper - Full size- Large space, heavy, tend to push you for paper notes


Equipment for Electronic Documents•

Good computer –

large resolution, memory, disk

space○Apple 24”

iMac with 1920x1200 resolution

•

Second display○Samsung 24”

T240 with 1920x1200 resolution

•

Wireless keyboard•

Wireless mouse


Other useful tools•

Internet access

•

Calculator•

Reference material

•

Printer•

Magnifying glass

•

Colored pens


Software•

Adobe Acrobat Reader and Apple Preview○Both allow opening PDF files but differ in features○Preview can easily combine single page files into

one document○Adobe Reader has a Pan & Zoom tool to view

smaller sections of a drawing•

Microsoft Word for Mac 2008○Generally compatible with Microsoft Word for

Windows with the exception of macros


Word Preview Adobe Acrobat


Three Project Stages for Design Review•

SD –

Schematic Design

•

DD –

Design Development•

CD –

Construction Documents


Performing the Design Review•

Understand what has been contracted

•

Read through the Project Specifications•

Check drawings against the drawing index○Complete set and most current version


Site Plans and Building Design


A key element in the electrical design is the Power Riser or One-Line...It may be simple

Electrical Design Reviewsor a bit more complex . . .


Voltages in building wiring•

Typical are 480VAC or 208VAC in a Δ

winding•

Typical are 480/277 VAC or 208/120 VAC in a Wye (Y) winding

•

Voltages typically stay the same or are reduced from the source to the user

•

As voltages go down the currents go up for the same power and so does the circuit losses (resistance)


Start with electrical distribution system•

Incoming power path○Switchboards, panel boards, transformers, etc.○Voltage, size, circuit protection, cable sizes

•

Switchboards and panel boards○One-lines match the schedules○Current and voltage ratings○Breakers, fuses, or MLO○Circuit balance on multi-phase circuits


Work through the drawings for …•

Lighting

•

Grounding•

Fire alarm systems

•

Exterior lighting•

Generator

•

ATS


Transformer and Wiring Example


Transformers•

Power capacity

•

Type•

Voltage

•

Correct number of conductors○Delta incoming –

3W + ground

○Wye –

4W conductors + ground


Transformer


Transformer Power Check:

Three-Phase Kilowatts = Volts x Amps x PF x 1.7321000

Transformer KWmax

= 480 x 175 x 1.0 x 1.732 / 1000KWmax

= 145.5 KW


Transformer Schedule

Protection = 145.5/112.5= 129% of rated load


Circuit Voltages


Transformer Schedule


Circuit Protection


Number of Conductors


Cables•

9

•

10•

25

•

26


Cables•

9 3 #2/0 & 1#6 GND

•

10 4-600KCMIL & 1#3 GND•

25 3 #1 & 1#6 GND

•

26 4 #4/0 & 1#4


Number of Conductors


Panels and Circuits


Not all observations noted are panels and circuitsYou are standing here.

Where is your exit?


What happens with the findings?•

Assembled with other disciplines results

•

Forwarded with recommendations to design team and copied to the owner

•

Design responses are returned and each issue is brought to resolution

•

All need resolution prior to contract award

Donald Zerrip

3075 Breckinridge Blvd.Duluth, GA 30096