Requirements and Expectations for Electrical Hazard Assessment Projects in Water and Wastewater Facilities

Presented by: Jay Bielanski, PE,

October 14, 2014

Topics

• Arc flash event• Introduction to electrical hazard analyses• Analysis software• Coordination with electric utility companies• Owner/operator efforts• Coordination of equipment shutdowns• Field collection• Assumptions to complete the study• Arc flash labels• Mitigation strategies• Project costs• Updating the study• Electrical safety program

Arc Flash Event (HRC 3)

Video by Westex, Inc.

Arc Flash Event

Introduction to Electrical Hazard Analyses

• Increase employee safety• Regulatory requirements

– OSHA – 29 CFR Part 1910 – Occupational Safety and Health Standards

– NFPA 70 – National Electrical Code– NFPA 70E – Standard for Electrical Safety in the

Workplace• Insurance requirements

5

Introduction to Electrical Hazard Analyses

• National Fire Protection Association 70E (NFPA)• Arc Flash Study

– Arc flash boundary– Incident energy at the working distance– Personal Protective Equipment required

• Short Circuit Study– Ability of the system equipment to handle fault

conditions

• Coordination Study– Optimal trip settings for selectivity, equipment and

personnel protection

• Shock Hazard Analysis– Voltage exposure– Boundary requirements– Personal Protective Equipment required

Analysis Software

• Software Options– PowerTools by SKM Systems Analysis– Network Analysis and Protective Device Coordination by

ETAP– Arc Flash Suite by EasyPower

Software Short Circuit Arc Flash Coordination Equipment Evaluation

SKM

ETAP

EP

Coordination With Electric Utility Companies

Coordination with Electric Utility Companies

• Request For Information– Primary service voltage– Secondary voltage– Transformer size– Transformer nameplate impedance– Transformer connection type– Transformer primary protective device– Available three phase fault contribution at the transformer primary– Available single phase to ground contribution at the transformer

primary– Three phase X/R ratio at the transformer primary– Single phase to ground X/R ratio at the transformer primary

Utility A

Utility B

Utility C

Coordination with Electric Utility Companies

• Data received is often:– Inconsistent– Maximum fault current values used for sizing services– Minimum or design guideline values for transformers– Estimated, rounded or manipulated numbers– Incorrect or missing!

• Experience is required to interpret data• Assumptions and estimations may be necessary

to provide realistic results or complete the study

Recommendations

• Electric utility contact should be the first action item!• Letter of authorization from owner to utility• Backup plan in case the utility does not follow through• Be sure that work is accomplished while waiting for a

response– Field investigation– System modeling– Develop operating scenarios– Prepare deliverables for review (reports, labels, electrical

safety program)

Availability of Facility Drawings

Availability of Facility Drawings

• Factors affecting usefulness of drawings– Type (as-built, design, shop)– Date– Accuracy

• One lines and plan drawings = faster modeling, field collection and labeling

Availability of Facility Drawings

• Case 1– 70+ facilities included in survey– Drawing for only 10% of facilities– Hand drawn one lines and

elevations were created

Availability of Facility Drawings

• Case 2– 7 facilities– No drawings– As-built CADD drawings were created

as part of project scope

Availability of Facility Drawings

• Case 3– 15 facilities– As-built for 80% of facilities

including record drawings of WWTP projects from 1955 through 2013

– No separate drawings required

Recommendations

• Drawings should be gathered at project inception• Availability of drawings should be made known to bidders

– Impact on cost and schedule

• If you do not have good drawings, make them a deliverable!

• Be aware of the effect on the project budget and schedule• Provide all available information at project kickoff

Owner/Operator Staff

Owner/Operator Staff

• Determine availability of staff– Designate a tour guide – Determine the level of assistance to be provided– Provide an employee able to answer questions

• Develop operating scenarios– What pumps are running in high and low flow events– What tie breakers are operated in contingency events– Are there alternate utility or generation sources

Access to Facilities

Access to Facilities

• Have a schedule and a plan• Follow the schedule and plan!• Ensure all parts of facilities are accessible• Provide a point of contact for each facility should a

revisit be required

Coordination of Equipment Shutdowns

Coordination of Equipment Shutdowns

• THINK SAFETY!• Is a shutdown possible without impacting

process?• If it is possible, schedule an outage• What duration is required for complete collection?• Have a contingency plan

Coordination of Equipment Shutdowns

• Determine what can be collected without a shutdown – Nameplates – Motor control centers, panelboards,

motors, transformers– Equipment locations and circuit length

• Determine what might require a shutdown– Motor control centers– Large panelboards,

switchboards, switchgear– Disconnect switches – Service entrance equipment– Equipment that is old or in

poor condition

Coordination of Equipment Shutdowns

Recommendations

• Coordinate efforts at project kickoff• Develop points of contact• Determine staff availability• Schedule facility access• Schedule equipment shutdowns• Schedule utility outages• Procedure for revisits• Think safety• Prepare to use assumptions where data is not

available• Have a schedule and a plan• Impact on cost and schedule

Field Collection

30

Field Collection

• ORGANIZATION!• One-lines• Data sheets• Photos

Data Sheets

• Switchgear (low or medium voltage)• Switchgear cubicles• Motor control centers (MCC)• Motor control center cubicles• Transformers• Generators• Panelboards• Automatic Transfer Switches (ATS)• Motors• Variable Frequency Drives (VFD)• Disconnects (switches, circuit breakers)

Photos

• Good photos can be the most useful tool• Paint a clear picture of the layout of a facility• More is better – if they’re organized!

Photos

Recommendations

• Determine deliverables– One lines/as-built information– Datasheets/asset information

• Opportunity to add value– One-line drawing development or verification– Condition assessment– Power reliability/redundancy analysis– Asset management synergies

Engineering Assumptions to Complete the Study

Engineering Assumptions

• Engineering assumptions are necessary to complete the study when reliable information cannot be provided or is not available

• Study parameters (i.e. utility input data)• Equipment (i.e. cable lengths, SCCRs)

Engineering Assumptions –Study Parameters

• Utilities often provide maximum possible fault current output or a wide range of parameters

• NFPA 70E: “Both larger and smaller available short-circuit currents could result in higher available arc flash energies.”

• Example:– Utility transformer: 750kVA– Transformer impedance: MAX = 5.00% MIN = 1.9%– Calculated fault current: = 18051 A = 47501 A– Difference: = 29450 A

Engineering Assumptions –Study Parameters

• Operating modes– What equipment is operating at minimum and

maximum flows?– What tie circuit breakers are operated in contingency

events?– Are there standby generators or alternate utility

services?

Engineering Assumptions –Equipment

• Short circuit current ratings– Conservative ratings

• Circuit breakers– Highest possible settings provide conservative results

• Cables– Sized per National Electrical Code, lengths estimated

• Transformers– Sized per manufacturer’s application guides

Arc Flash Labels

Arc Flash Labels

• What equipment gets labeled? • 2011 NEC 110.16 Arc Flash Hazard Warning:

“Electrical equipment, such as switchboards, panelboards, industrial control panels, meter socket enclosures, and motor control centers, that are in other than dwelling units, and are likely to require examination, adjustment, servicing, or maintenance while energized shall be field marked to warn qualified persons of the potential electric arc flash hazards.”

4 Enclosures

36 Enclosures

Arc Flash Labels

• How many labels for larger equipment?

71 Labels6 Labels

Label Format

• Labels must have at least one of the following:– Available incident energy and the corresponding

working distance– Minimum arc rating of clothing– Required level of Personal Protective Equipment (PPE)– Highest Hazard/Risk Category (HRC) for the equipment

• Nominal system voltage• Arc flash boundary

Label Format

Recommendations

• Owner/operator preference for design• What fits with the safety program• Education and training• Label requirements should be established at

project inception and should be consistent• Impact on cost and schedule

Mitigation Strategies

Mitigation Strategies

• Low cost– Settings changes

Mitigation Strategies

• Medium cost– Fuse replacement– Breaker

replacement– Relay replacement– Trip unit upgrades– ARMS devices

Mitigation Strategies

• High cost– Zone Selective

Interlocking– Optical relays– Differential

protection

Recommendations

• Explore all options (One size does not fit all!)

Existing settings

Equipment upgradesEquipment replacement

Advanced strategies• Remove the worker from the hazard

– Remote operation, remote racking, mimic panels

Project Costs

Project Costs

• Many determining factors– How many facilities? What sizes?– What equipment is included in the study?– What level of field collection effort is required?– What equipment is being labeled? How many

labels?– Are there additional services?

• Electrical Safety Program, CAD drawings, Condition Assessment, Training

How Many Zeroes Do I Need?

• Small pumping station– ≈$5,000 - $15,000

• Large pumping station– ≈$10,000 - $50,000

• Small – mid size treatment plant– ≈$25,000 - $50,000

• Large treatment plant– ≈$50,000 - $150,000+

Updating the Study

Recommendations

• Required by NFPA 70E• Update after any major modifications are

made to the electrical distribution system– What is a “major” modification?

• Review the study every five years

Electrical Safety Program

Electrical Safety Program

• Do not view the project as a requirement; view it as a tool!

• Educate personnel – electrical safety program• Have a consistent electrical safety program at all

facilities– Consistent labels– Consistent procedures

• Know how to interpret labels• Two-level clothing system and other methods to

improve ease of use

Two Level Clothing System

Category 4Category 2

Summary

• Assemble all facility data and plan to make it available to potential bidders

• Make important decisions at project inception• If you do not know, ask!

QUESTIONS?Thank you for your time!jbielanski@greeley-hansen.com