Area Classifications (www.eBookByte.com)

KUWAIT NATIONAL PETROLEUM COMPANY SAFETY REGULATIONS

CHAPTER – 1

AREA  CLASSIFICATIONS

IMPORTANT

Mandatory rules (or "must") are characterised by the word "SHALL" throughout the text. Advisory rules or recommendations are indicated by the word "SHOULD." The words shall and should have been used to remain in line with the terminology used by American National Standard Institute.

REFERENCES API-RP 500A, NFPA-497, NEC Article-500, IP standards, KNPC standards

CHAPTER – 1   PAGE – 1 of 6  

REVISION – 1 REVISION – 0

KNPC SAFETY COMMITTEE

MAY 1998 JUNE 1994

KUWAIT NATIONAL PETROLEUM COMPANY

CHAPTER - 1

SAFETY REGULATIONS

REVISION - 1

PAGE - 2 of 6 MAY 98

AREA CLASSIFICATIONS TABLE OF CONTENTS PAGE 1.1

1.2

INTRODUCTION

 

 

 

 

 

1.1.1

 

CONTROLLED AREA

 

1.1.2

 

RESTRICTED AREA

 

 

1.1.3

 

HAZARDOUS AREA

 

 

1.1.4

 

NON-HAZARDOUS AREA

 

1.2.2  

CLASS

 

 

 

 

HAZARDOUS AREA CLASSIFICATION 1.2.1

 

 

  3

 

 

3

 

 

3

 

 

 

 

 

 

 

1.3

4  

4

GROUPING OF FLAMMABLE OR COMBUSTIBLE MATERIALS            

CLASS II MATERIALS - DUST

1.2.4  

3

 

CLASS I MATERIALS GASES AND VAPORS  

1.2.3

3

 

 

 

 

 

 

 

 

 

CLASS III COMBUSTIBLE FIBRES

 

 

DIVISION

 

 

 

 

 

4 5 5  

RELATIONSHIP BETWEEN DIVISION AND ZONE

AREA CLASSIFICATION FOR WORK PERMITS

 

1.3.1 WORK PERMIT AREA

 

 

 

1.3.2 WORK PERMIT FREE AREA

 

KNPC SAFETY COMMITTEE 

   

 

 

4

 

5

6

6

   

6 6

KUWAIT NATIONAL PETROLEUM COMPANY

CHAPTER - 1

SAFETY REGULATIONS

REVISION - 1

PAGE - 3 of 6 MAY 98

AREA CLASSIFICATIONS 1.1

INTRODUCTION

Substances handled by petroleum installation include flammable and combustible liquids / vapours and gases. To have a safe work environment, hazards need to be identified in work places and effective controls needs to be developed. In view of the above our premises have been broadly defined as: (a) (b) (c)

Controlled area Restricted area Hazardous area 1.1.1  CONTROLLED AREA

“Controlled Area” is the entire KNPC premises fenced or otherwise, to which access is controlled or restricted. 1.1.2 RESTRICTED AREA

“Restricted area” is within the “Controlled area” in which entry is permitted only to authorized persons and a valid gate pass is necessary to enter these premises. 1.1.3 HAZARDOUS AREA

“Hazardous area” is the area within the “Restricted area” where flammable atmosphere is more likely to be present. A flammable atmosphere is defined as having sufficient concentration of flammable gas, vapor, mist or combustible dust, capable of being ignited.

1.1.4 NON-HAZARDOUS AREA

A Non-Hazardous Area is the area within the controlled area or restricted area, which is not classified as a hazardous area.

KNPC SAFETY COMMITTEE 

KUWAIT NATIONAL PETROLEUM COMPANY

CHAPTER - 1

SAFETY REGULATIONS

REVISION - 1

PAGE - 4 of 6 MAY 98

1.2   HAZARDOUS AREA CLASSIFICATION

Use of hazardous area classification system helps in identifying the extent of areas in which explosive mixtures with air may occur under normal and expected abnormal conditions. In this system, areas are classified and grouped according to the flammable/combustible materials, which may be present. Class-I    - Group A,B,C,D include all flammable gases and liquids. Class-II   -  Group E,F,G include all combustible dusts. Class-III  -  All combustible fibers. The classified areas are further subdivided into Division-1 and Division-2 areas. Industry standards and work practices, which deal with area classification, are API-RP-500A, NFPA-497, NEC Article-500 and IP model code of Safety. KNPC standards are in line with these standards. Hazardous Area classification is used for proper selection and safe installation of electrical/instrument equipment. However, these should also be considered while locating or installing other equipment, which may present an ignition source, e.g. fired heater, boiler, IC engines, welding machines etc. 1.2.1   CLASS Class-I locations are those in which flammable gases or vapors are or may be present in the air in quantities sufficient to produce explosive or ignitable mixtures. Class-II locations are those that are hazardous because of the presence of combustible dust. (Ex: coke) Class III locations deal with combustible fibers. (Not applicable in KNPC)

KNPC SAFETY COMMITTEE 

KUWAIT NATIONAL PETROLEUM COMPANY

CHAPTER - 1

SAFETY REGULATIONS

REVISION - 1

PAGE - 5 of 6 MAY 98

1.2.2 GROUPING OF FLAMMABLE OR COMBUSTIBLE MATERIALS

Depending on the  type of flammable material, classified areas are categorised in accordance with material groups descibed as A,B,C, etc.

CLASS I MATERIALS - GASES AND VAPORS

These are divided into groups A, B, C & D. Following are groups of common materials in KNPC:Group - A

Acetylene

Group - B

Hydrogen, Ethylene.

Group - C

Hydrogen Sulphide or gases or vapours of equivalent  hazard.

Group - D

Most Hydrocarbons e.g. Benzene, Butane, Propane, gasoline, Naphtha etc.

CLASS II MATERIALS - DUST

Group - E   Metal dust Group - F

Carbonaceous dust (Coke dust, charcoal, coal, and carbon black).

Group - G

Other dust, flour, starch, grain dust.

CLASS III MATERIALS - COMBUSTIBLE FIBRES (not applicable in KNPC)

1.2.3 DIVISION

Having decided that a location should be classified, and having designated the gas or vapor as group A, B, C or D, the next step is to designate the location as either Division-1 or Division-2. Division 1 – Locations where explosive mixtures are likely to exist under normal operating condition, e.g. area immediately surrounding open vents or open transfer of flammable or combustible materials. Division 2 - Location where explosive mixtures may occur under abnormal conditions, e.g. equipment leakages or failure.

KNPC SAFETY COMMITTEE 

KUWAIT NATIONAL PETROLEUM COMPANY

CHAPTER - 1

SAFETY REGULATIONS

REVISION - 1

PAGE - 6 of 6 MAY 98

1.2.5 RELATIONSHIP BETWEEN DIVISION AND ZONE

In KNPC engineering drawings hazardous areas are classified as per US standards. There is no technical equivalent relationship between this system and the “Zone" categorisation followed in Europe. The final selection shall be the responsibility of the respective authority.   However for guidance purpose, the following table provides a rough comparison. Division (US)

Class-I

1.3.1

 

Flammable Gas Area

Class-I Div1    

Zone 0 or 1

Class-I Div2

Zone 2

Class-II

1.3

 

Zone (EU)

 

     

Combustible dust area

Class-II Div1

   

Zone ‘Z’

Class-II Div2

   

Zone ‘Y’

AREA CLASSIFICATION FOR WORK PERMITS WORK PERMIT AREA

In general, “controlled area” shall be considered as “work permit area” with following exceptions: a) Areas classified as ‘ Work Permit Free Area’ b) Routine activities in ‘Non-Hazardous Area’ such as office work, driving vehicles along unrestricted roads etc. 1.3.2

WORK PERMIT FREE AREA

Certain areas within the restricted area may be designated as a ‘Work Permit Free Area’ for a defined task as approved by KNPC Safety, e.g., approved smoking areas, areas designated for pre-fabrication work, Workshops, etc. Such areas are to be clearly indicated.

KNPC SAFETY COMMITTEE