Type Y & Z NFPA 496 Enclosure Pressurization Units Model Number Matrix

Unit Model Number Matrix

The Model Number Segments below specify standard features and options for our Enclosure Pressurization Units. Please note limitations to various selections apply as indicated by an asterisk and note number in red text.

Typical Model Number:

Model
Number:

YZ

-

101A

-

CI/CII

-

B

-

V

-

24

Segments:

1

-

2

-

3

-

4

-

5

-

6

Model
Number:

YZ

-

101A

-

CI/CII

-

Segments:

1

-

2

-

3

-

Model
Number:

B

-

V

-

24

-

Segments:

4

-

5

-

6

-

1 – Unit Type
 
YDivision 1 / Zone 1 to Division 2 / Zone 2
ZDivision 2 / Zone 2 to Non-Hazardous
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Best Purging Systems combines Type Y & Z Purging and Pressurization Technology into a single unit to make acquisition and use simple. When utilized in Division 2 / Zone 2 Classified Hazardous Locations, our units are certified to reduce the hazardous location rating inside your protected enclosure from Division 2/ Zone 2 to non-hazardous. This allows the use of non-rated equipment in Division 2/ Zone 2 areas. While seldom required, when utilized on Division 1 / Zone 1 Classified Hazardous Locations, our units are certified to reduce the hazardous location rating inside your protected enclosure from Division 1/ Zone 1 to Division 2 / Zone 2. This allows the use of Division 2/ Zone 2 equipment in Division 1/ Zone 1 areas.

2 – Unit Series
 
101AClass I Purge Unit – 2 CF Maximum

Class II Pressurization Unit – 10 CF Maximum
101BClass II Pressurization Unit – 50 CF Maximum
101CClass II Pressurization Unit – 250 CF Maximum
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Best Purging Systems Type Y and Z Pressurization Units are manufactured in three sizes to accommodate various protected enclosure volumes. The Model 101A features a 1/4” enclosure pressure supply regulator, while the Model 101B and 101C feature 3/8” and 1/2” supply regulators, respectively. As regulator size increases, capacity to hold the required safe pressure is increased. As rated, Model 101A is suitable for a total enclosure volume of 2 Cubic Feet in Class I Areas and 10 Cubic Feet in Class II Areas. Model 101B is suitable for volumes not exceeding 50 cubic feet in Class II Areas, and Model 101C is suitable for volumes not exceeding 250 cubic feet in Class II Areas. In all instances, total volume may not exclude any volume consumed by internal equipment.

3 – Area Classification 
CI/CIIClass I / Class II – Model 101A
CIIClass II – Models 101B & 101C
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The Best Purging Systems Classified Rating distinguishes the exact purpose of the Model and indicates the Class or Classes, as established by the National Electric Code, Article 500. Class I Areas are considered as areas that may contain flammable concentrations of gases or vapors. In this instance, it is imperative to purge a protected enclosure to eliminate such potential concentrations before applying power to unrated devices within the enclosure. Class II Areas are considered as areas that may contain ignitable concentrations of airborne particles, dust or fibers. In this instance, it is imperative to clean a protected enclosure to eliminate such potential concentrations before applying power to unrated devices within the enclosure.

4 – Pressure Switch Option  *1 

L

Less Switch

W

Class I, Group C & D / Class II,
Group E, F & G Switch

B

Class I, Group B, C & D Switch
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Best Purging Systems uses this segment to specify whether an enclosure pressure loss alarm switch is integrated with your unit, and if so, what electrical classification rating it meets. Universal Units are sold without an integrated switch, and thus require the “L” designator. Best Purging Systems offers Model EPSK Explosion Proof Pressure Switch Kits which may be mounted separately either internal to or external to the protected enclosure to activate an audible or visual alarm when required. “W” indicates the integration of a Class I or II, Division 1 or 2 Group C, D, E, F & G rated pressure switch for Horizontal and Vertical Mount Units. “B” indicates the integration of a Class I Division 1 or 2 Group A, B, C & D rated pressure switch for Horizontal and Vertical Mount Units.

5 – Mounting Configuration  *2 
UUniversal
VVertical
HHorizontal
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Best Purging Systems provides Type Y and Z Purging and Pressurization Units in three configurations. The Universal Mount Units have symmetrical dimensions, and may be flange mounted on any side of a protected enclosure. In addition, since they do not feature an integrated enclosure pressure loss alarm switch, they may also be mounted through any surface or door of a protected enclosure with the addition of a Model PMGK Panel Mount Gasket Kit. Our Vertical Mount Unit may be mounted on the left of right side of a protected enclosure, and is our most popular model due to its overall convenience of use. However, to ensure maximum flexibility, we also offer Horizontal Mount Units for the top or bottom side of your protected enclosure.

6 – Group B Switch Voltage  *3 
2424 VDC
120120 VAC
240240 VAC
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As an optional segment, necessary only for Vertical or Horizontal Mount Units with the Group B enclosure pressure loss alarm switches, this segment specifies the required operating voltage. The Class I or II, Division 1 or 2 Group C, D, E, F & G rated pressure switch provided when “W” is selected under Segment 4 is provided with a simple form C dry contact and requires no power source to operate. However, the Dwyer pressure switch rated for Class I Division 1 or 2 Group A, B, C & D requires a power source to operate its form C contact. To ensure maximum flexibility, Best Purging Systems offers all three available operating voltages of 24 VDC, 120 VAC and 240 VAC. However, due to rarity of use, the 240 VAC Unit is not stocked, and built only upon order.

* MODEL NUMBER SELECTION NOTES:

  1. Please select “L” for Universal Mounting Configuration and note Option “B” is available for Model 101A only.
  2. Universal Mount Unit is suitable for Panel Mount Kit.
  3. For Pressure Switch Option “B” only – please omit if not applicable.

Please consult a Best Purging Systems Corporation Sales Associate for more information and unit customization.