P01_Arc Flash Hazard Analysis Newington.pdf

6-1

6. ARC FLASH HAZARD ANALYSIS

6.1. Introduction

An arc flash risk assessment determines arc flash hazards, arising from incident energy released by an arcing fault, at specified devices in the electrical distribution system. Of critical interest are locations where maintenance personnel will likely perform work on energized equipment such as switchgear, switchboards, panelboards, industrial control enclosures, and panelboards. NFPA 70E, 2018, 130.5(D) requires arc flash labels containing the nominal system voltage, arc flash boundary, available incident energy, and corresponding working distance for all such equipment.

The analysis performed per NFPA 70E, 2018, determines the Flash Protection

Boundary and the personal protective equipment (PPE) to be used within arc flash boundaries higher than 1.2 cal./cm2.

This study has been completed based on the IEEE 1584-2018 standard. This guide utilizes similar parameters as IEEE 1584-2002, with the addition of bus bar configurations and box enclosure dimensions.

6.2. Arc Flash Calculations

Calculations have been made per IEEE 1584, 2018 with a clear fault threshold of

80%, a maximum arcing duration of 2.0 seconds, and the inclusion of induction motors for 5 cycles.

6.3. Arc Flash Hazard Analysis

The Arc Flash Risk Assessment has been performed per NFPA 70E with the worst-case results across all scenarios reported. Equipment with a calculated incident energy of 12.0 cal./cm2 or higher is highlighted in the Arc Flash Reports. TMM recommends that all existing arc flash hazard labels are removed and only labels that are provided with this study be installed.

The calculated incident energy exceeds 40 cal./cm2 at the locations listed below.

Energized work should be performed at these locations under permit only.

4-MAIN-ECB (Bldg. 4 Bsmt) (4-MAIN-ECB-CB LineSide)

2W-MDP (Rm. 2W-B00)

65-GEN-MDP-FDS (Ext. 65) (65-GEN-MDP-FDS-FU LineSide)

65-N4CHP11 (Rm. 114) (65-N4CHP11-MB LineSide)

MV-XF-4-SEC (South Courtyard)

MV-XF-30-A-SEC (South Courtyard)

MV-XF-30-B-SEC (South Courtyard)

MV-XF-65-GEN-MDP-SEC (Ext. 65)

Arc Flash labels will be provided in the VAMC’s copy of the final submittal for installation by the electrical maintenance staff. WARNING labels are provided for equipment with a calculated incident energy less than 40 cal./cm2 and DANGER

6-2 labels are provided for underrated equipment and all equipment with a calculated incident energy exceeding 40 cal./cm2.

Sample labels are presented below:

6-3

6.4. Personal Protective Equipment (PPE)

The table below, excerpted from NFPA 2018, delineates the clothing and PPE required for the indicated levels of incident energy:

Table 130.5(G) Selection of Arc-Rated Clothing and Other PPE When the

Incident Energy Analysis Method Is Used

Incident energy exposures equal to 1.2 cal/cm2 up to 12 cal/cm2

Arc-rated clothing with an arc rating equal to or greater than the estimated incident energy a

Long-sleeve shirt and pants or coverall or arc flash suit (SR)

Arc-rated face shield and arc-rated balaclava or arc flash suit hood (SR) b

Arc-rated outerwear (e.g., jacket, parka, rainwear, hard hat liner) (AN)

Heavy-duty leather gloves, arc-rated gloves, or rubber insulating gloves with leather protectors (SR) c

Hard hat

Safety glasses or safety goggles (SR)

Hearing protection

Leather footwear

Incident energy exposures greater than 12 cal/cm2

Arc-rated clothing with an arc rating equal to or greater than the estimated incident energy a

Long-sleeve shirt and pants or coverall or arc flash suit (SR)

Arc-rated arc flash suit hood

Arc-rated outerwear (e.g., jacket, parka, rainwear, hard hat liner) (AN)

Arc-rated gloves or rubber insulating gloves with leather protectors (SR) c

Hard hat

Safety glasses or safety goggles (SR)

Hearing protection

Leather footwear

SR: Selection of one in group is required.

AN: As needed.

a Arc ratings can be for a single layer, such as an arc-rated shirt and pants or a coverall, or for an arc flash suit or a multi-layer system if tested as a combination consisting of an arc-rated shirt and pants, coverall, and arc flash suit.

b Face shields with a wrap-around guarding to protect the face, chin, forehead, ears, and neck area are required by 130.7(C)(10)(c). Where the back of the head is inside the arc flash boundary, a balaclava or an arc flash hood shall be required for full head and neck protection.

c Rubber insulating gloves with leather protectors provide arc flash protection in addition to shock protection. Higher class rubber insulating gloves with leather protectors, due to their increased material thickness, provide increased arc flash protection.