safety on rangehood from a perspective of ul 507

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ByMay, 2009

Safety onRangehood based on UL 507

工程师

Please make sure your cell pone in mute mode, thanks.

Intention of Safety Regulation

Construction Review

(10 min.)

(120 min.)

(15 min.)

Marking and Instruction

ObjectiveTo Be In Awareness of

“You have to learn the rules of the game. And then you have to play better than anyone else.”

Intention of Safety Regulation

Safety Regulation

TO assure safe and healthful working and living conditions for people to prevent loss of life and property damage.

Why not protect the safety of life and property?

Because…

pre·ventVerb, Archaic

To anticipate or counter in advance.

prevent protectvs.

Now youNow you know the

sudiffe

know

btlerence

Safety Regulation

To prescribe standards to establish benchmarks for all industries

Just

You will see…

So…

To assure safe and healthful working conditions for working men and women; by authorizing enforcement of the standards developed under the Act; by assisting and encouraging the States in their efforts to assure safe and healthful working conditions; by providing for research, information, education, and training in the field of occupational safety and health; and for other purposes.

the original

The OSH Act 1970Occupational Safety and Health Act of 1970

December 29, 1970

Legislation need be embodied into regulations such as 29 CFR.

29 CFR (Code of Federal Regulations)

Industries work out the nitty-gritty requirements which constitute of various standards.

Nationally Recognized Testing Laboratory (NRTL)

OSHA need authorize and monitor private sector organizations, so NRTL program came into existence.

In the evaluation of the NRTLs, OSHA will use either consensus-based standardscurrently in use nationally, or other standards or criteria which may be considered appropriate.

The NRTL determines that specific equipment and materials ("products") meet consensus-based standards of safety to provide the assurance, required by OSHA, that these products are safe for use in the U.S. workplace.

s are third-party organizations recognizedby OSHA as having the capability to provide productsafety testing and certification services to themanufacturers of a wide range of products for use in the American workplace.

The testing and certifications are based on productsafety standards developed by U.S.-based standards developing organizations and often issued by the American National Standards Institute (ANSI).

NRTL

Many product “approval” requirements are found in OSHA’s standards (29 CFR Parts 1910, 1915, 1918, and 1926). Approval, i.e., NRTL testing and certification, is required for many types of products, including

– Electrical equipment

– Fire detecting and extinguishing equipment

– Liquefied Petroleum Gas (LPG) utilization equipment

– Equipment to be used in hazardous locations

Regulations can only assure relative safety, not absolute!

Id

u s tr y R e

a l i t y

nSafety

Standards are the compromise between safety&health and industry reality such as cost, technology!

Testing are simulation of reality, not reality!

Construction Review

Hazards

Hazards

Electric Shock

Mechanical Hazard

Fire Hazard

Tempered Glass

Enclosure

Filter

Mounting Means

Power Supply Cord

Impeller (blower wheel)

Ⅰ

Ⅲ

Ⅱ

Ⅳ

Duct

Ⅰ

Your skin is your first protection from the world,

for appliance, so is Enclosure!

2.3.3 ENCLOSURE - That part of the product that:

a) Renders inaccessible all or any parts of the fan that present a risk of electric shock or injury to persons due to total or partial collapse with a resulting reduction of spacings, loosening or displacement of parts, or other serious defects; or

b) Retards propagation of flame initiated by electrical disturbances occurring within.

Fire

Fire

2.3.3 ENCLOSURE - That part of the product that:

a) Renders inaccessible all or any parts of the fan that present a risk of electric shock or injury to persons due to total or partial collapse with a resulting reduction of spacings, loosening or displacement of parts, or other serious defects; or

b) Retards propagation of flame initiated by electrical disturbances occurring within.

Enclosure Material:Metal

Gavanized sheet steel, 0.74 mmUncoated sheet steel, 0.66 mm

Nonferrous sheet steel, 0.91 mm

Non-MetalPolymeric material, ? mm

6.3 Non-metallic enclosures

6.3.1 A non-metallic enclosure shall comply with the applicable mechanical and electrical property considerations, flammability, and thermal requirements as specified in the Standard for Polymeric Materials - Use in Electrical Equipment Evaluations, UL 746C.

UL 746C:

Mechanical requirement:Ball Impact Test [polymeric enclosure]

This ball?

Mechanical requirement:Static Load Test For Mounting Means [complete unit]

Mechanical requirement:Mold Stress Relief Test [polymeric parts]

Internal Stress results from molding or fabrication process!

BECAUSE

2.3.3 ENCLOSURE - That part of the product that:

a) Renders inaccessible all or any parts of the fan that present a risk of electric shock or injury to persons due to total or partial collapse with a resulting reduction of spacings, loosening or displacement of parts, or other serious defects; or

b) Retards propagation of flame initiated by electrical disturbances occurring within.

8 Accessibility of Moving Parts :

9 Accessibility of Live Parts :

Tempered Glass

Enclosure

Filter

Mounting Means

Power Supply Cord

Impeller (blower wheel)

Ⅱ

Duct

ⅡEntirely of metal

Filter

Activated carbon contained [R/C as Class 1 or 2 to UL 900]

A REUSEABLE METAL

Filter can act as safeguardagainst mechanical hazard such as rotating impeller

Tempered Glass

Enclosure

Filter

Mounting Means

Power Supply Cord

Impeller (blower wheel)

Ⅲ

Duct

ⅢMetal

Impeller

Polymeric material

Polymeric Impeller Material parameters:

HDT [Heat Deflection Temperature]

75 ℃ @ 455.07 kPa

RTI 60 ℃

Polymeric Impeller Material parameters:

HDT [Heat Deflection Temperature]

75 ℃ @ 455.07 kPa

UL 746C:

Tempered Glass

Enclosure

Filter

Mounting Means

Power Supply Cord

Impeller (blower wheel)

Ⅳ

Duct

ⅣPower supply cord

POWER SUPPY

Field wiring

Power supply cord:

91.6.4 For cord-connected rangehoods, the cord type shall be one of the following: HS, HSO, HSJ, HSJO, S, SE, SO, SOO, ST, STO, STOO, SJ, SJO, SJOO, SJT, SJTO, or SJTOO.

Power supply cord:

91.6.5 The length of a rangehood cord shall not be less than 3 ft (0.9 m) and shall not be more than 4 ft (1.22 m),

3 ft (0.9 m) ≤ length ≤ 4 ft (1.22 m)

Power supply cord:

91.6.8 The attachment plug of a power supply cord for a cord-connected rangehood shall be of the grounding type.

Power supply cord:

91.6.11 A flexible power supply cord for a cord-connected rangehood shall vertically exit the top-most horizontal surface of the rangehood.

Field wiring:

Article 300 – Wiring Method300.15 Boxes, Conduit Bodies, or Fittings —Where Required

152.4 mm (6 inches):

Wiring terminals and leads:

Length ≥152.4 mm (6 inches)

Wiring terminals and leads:

Leads ≥ 18 AWG

Wiring terminalsand leads:

Terminal Screw ≥ No. 10 (4.8 mm)

Wiring terminalsand leads:A = fixed part

B = washer or clamping plate

C = anti-spread device

D = conductor space

Screws need retaining means for conductors, such as upturned lugs, a cupped washer, or the equivalent

Field Wiring compartment:Openings for conduit

Field Wiring compartment:Openings for conduit

knockout

Surrounding flat surface

26.29Φ

79.038.022.22 +

−Φ

Unit: mm

Field Wiring compartment:the area surrounding the knockout

knockout26.29Φ

Surrounding flat surface

Unit: mm

Field Wiring compartment:the area surrounding the knockout

26.29Φ

The thickness of sheet steel at grey area ≥ 0.81 mm

Field Wiring compartment:Volume Calculation

Field Wiring compartment:Volume Calculation

Note - The usable volume of terminal compartments should be considered the net volume less the volume of any components located within the terminal compartment such as capacitors, switches, relays, and terminal blocks.

Field Wiring compartment:Volume CalculationFor a given rangehood which employs 2 supply leads of 18AWG plus 1 grounding lead, there are 1 capacitor of 4 cm by 3 cm by 1 cm within the field wiring compartment:

Branch supply conductors within House, 14 AWG

Field Wiring compartment:Volume Calculation

32.4926.24 cm=×Usable(net)

2 supply leads within appliance

331.98377.32 cm=×2 branch supply conductors plus 1

equipment grounding conductor

Tare312134 cm=××1 capacitor

Field Wiring compartment:Volume CalculationGross = Usable(net) + Tare

351.1591231.982.49 cm=++

Tempered Glass

Non-shattering or

Tempered Glass

UNDERWRITERS LABORATORIES

CERTIFICATION REQUIREMENT DECISION

92.7Loading test for glass rangehood surfaces

92.8 Tempered glass impact test

20070814

92.8 Tempered glass impact test

Section 5.1

Impact Test

Marking and Instruction

Duct

Enclosure

Mounting Means

Power Supply Cord

LampUL 1598

ICC

ClearanceAHJ

NFPA

Rating Label

(e) Marking—

(2) Durability. The marking shall be

of sufficient durability to withstand

the environment involved.

(1) Identification of manufacturer

and ratings. Electric equipment

may not be used unless the following

markings have been placed on

the equipment:

(i) The manufacturer’s name, trademark,

or other descriptive marking by

which the organization responsible for

the product may be identified; and

(ii) Other markings giving voltage,

current, wattage, or other ratings as

necessary.29CFR1910.303

62.1 General

62.1.1 An appliance shall be plainly and permanently marked where visible with:

a) The manufacturer's name, trademark, or other descriptive marking by which the organization responsible for the product is identified - hereinafter referred to as the manufacturer's name;

b) A distinctive catalog number or the equivalent;

c) The electrical rating; and

d) The date or other dating period of manufacture not exceeding any three consecutive months. See 62.1.2.

For a permanently-connected appliance, the marking shall be visible after installation.

UL 507

DANGER-

WARNING-

CAUTION-

Mounting MeansDuct

Installation Instruction

64A.3 A small part not provided with the appliance for mounting shall be referenced in the installation instructions.

64A.4 An accessory for a permanently installed fan shall be provided with instructions detailing proper installation procedures.

To Identify

Remote blower assemblies

CONSTRUCTION Ducted

Integral blower assemblies

Non-ductedCeiling/Island Mount

Wall Mount

Under-Cabinet Mount

INSTALLATION

Downdraft

by