IEEE 1202 Flame Propagation Testing of Wire and Cable

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IEEE Standard for Flame-Propagation Testing of Wire and Cable





Sponsor
Insulated Conductors  Committee
of the
IEEE Power Engineering Society


Approved 8 June 2006

IEEE-SA Standards Board

Contents
1.   Overview   1
1.1   Scope   1
1.2   Purpose   1
1.3 Applications ...   I
1.4 Disclaimer. ...   I
1.5 Test precautions ...   I
2.   Normative  references   1
3.   Definitions   1
4. Flame test facility ...   I
4.I Enclosure   1
4.2   Exhaust duct   4
4.3   Air movement within the enclosure   4
4.4   Cable tray   5
4.5   Burner and mixer   5
4.6   Flowmeters   6
4.7   Supply air   6
4.8   Propane   6
5.   Test sample requirements   6
5.1   Cable samples   6
5.2   Tests required   7
6.   Flame test procedure   7
6.1   Cable mounting   7
6.2   Test  procedure   9
7.   Test evaluation   10
7.1   Evaluation of damage   10
7.2 Performance criteria ...   Il
7.3 Test report ...   Il Annex A (normative) Burner and mixer information   12
Annex B (informative) Bibliography   14


IEEE Standard for Flame-Propagation Testing of Wire and Cable






1.   Overview



1.1   Scope

This standard provides a protocol for exposing cable samples to a theoretical20 kW (70 000 Btu/h) flaming ignition source for a 20-min test duration. The test determines the flame propagation tendency of single­ conductor and multi-conductor cables intended for use in cable trays.


1.2   Purpose

The purpose of this standard is to establish a test protocol and performance criteria to determine the flame propagation tendency of cables in a vertical cable tray.


1.3   Applications

This standard shall apply to multi-conductor cables and single insulated conductors that are allowed to be installed in cable tray, or to other cables and conductors for which a flame rating to the requirements of this standard is desired.


1.4   Disclaimer

The results obtained using this test do not imply that cables of similar cable construction will necessarily perform the same way in other cable arrangements, other cable tray configurations, or other environments.


1.5   Test precautions

Fire  testing  of products  and  materials  is  inherently  hazardous.  Adequate  safeguards  for  personnel  and property shall be employed while conducting these tests.

2.   Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated  references, the latest edition of the referenced document (including any amendments or corrigenda) applies.

ANSI/ASTM 01835-2005, Specification for Liquefied Petroleum (LP) Gases.' ASTM C90-2005, Standard Specification for Loadbearing Concrete Masonry Units.2
CAN/CSGB 3.14-06, Liquefied Petroleum Gas (Propane), Canadian General Standards Board.3

CSA Standard C22.2, No. 126.1-02, Metal Cable Tray Systems, Second Edition.4

IEC 60332-3-10-2000, Tests on Electric Cables under Fire Conditions-Part 3-10: Test for Vertical Flame Spread of Vertically-Mounted Bunched Wires or Cables-Apparatus, First Edition.5

NEMA VE 1-2002, Metal Cable Tray Systems.6


3. Definitions

For the purposes  of this document, the following terms and definitions apply. The Authoritative  Dictionary of IEEE Standard  Terms [B3f should be referenced  for terms not defined in this clause.

3.1 sample: The insulated conductor or cable type and construction to be tested.

3.2 specimen: The individual length of cable or cable bundle to be placed in the cable tray for testing.


4.   Flame test facility

4.1 Enclosure

Figure I provides a typical example of an enclosure in which the sample is tested. The inclusion of a baffle for safety purposes to protect the hood, duct, and fan (shown in Figure I) is optional.







1   ANSI publications are available from the Sales Department, American National Standards Institute, 25 West 43rd Street, 4th Floor, New York, NY 10036, USA (You are not allowed to view links. Register or Login
2   ASTM publications are available from the American Society for Testing and Materials, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, USA (You are not allowed to view links. Register or Login
3   Canadian General Standards are available from the Canadian General Standards Board, Place du Portage III, 6B I, II Laurier Street, Gatineau, Quebec, Canada KIA IG6 (You are not allowed to view links. Register or Login
4   CSA publications are available from the Canadian Standards Association, 5060 Spectrum Way, Suite I 00, Mississauga, Ontario, Canada, L4W SN6.
5   IEC publications are available from the Sales Department of the International Electrotechnical Commission, Case Postale 131, 3, rue de Varembe, CH-1211, Geneve 20, Switzerland/Suisse (You are not allowed to view links. Register or Login). IEC publications are also available in the United States from the Sales Department, American National Standards Institute, II West 42nd Street, 13th Floor, New York, NY 10036, USA.
6   NEMA publications are available from Global Engineering Documents, 15 Inverness Way East, Englewood, Colorado 80112, USA (You are not allowed to view links. Register or Login
7   The numbers in brackets correspond to those in the bibliography in Annex B.



Legend:

!-Enclosure. Concrete blocks, if used, should be the standard commercial size available such as trade size 8 in x 16 in x 6 in or the equivalent in metric trade size such as 200 mm x 400 mm x I SO mm. (The exact block size is not significant to the test results; however, the air intake opening size is critical.)
2-   Steel-framed door with wired-glass window for access and observation. The size ofthe door should be a standard commercial door size such as trade size 36
x 84 in or the equivalent metric trade size such as Ix 2 m.
3-   Stcel-framed wired-glass observation window(s) nominally 450 mm (18 in) square, located on a side wall of the chamber (see 4.1.2).
4--Truncated-pyramid stainless-steel hood; each side is sloped approximately 40".
5--Collection box with exhaust duct centered on one side. The box shall be a cube with each face a 910 mm ± 15 mm (36 in ± 0.5 in) square. 6-Tray mounted vertically in the center of the enclosure.
7-   Air-intakc openings.
8-   Steel baffle that is nominally 610 mm x 610 mm (24 in x 24 in) and 3.2 mm (0.125 in) thick. 9-Duct that is 405 mm ± 15 mm (16 in± 0.5 in) inside diameter.
10-   ighting (optional).
11-   Fiarne height gauge (optional).
12-   Temperature probe (Type K thermocouple with inconel sheath). 13-Bidirectional  velocity  probe.
14-Photoelectric cell and light source for smoke density measurement (optional).
15--Control cabinet(s) for bidirectional velocity probe, thermocouple, light source, and photoelectric cell (optional). 16-Ribbon   burner.
Figure 1-Fiame test enclosure


The enclosure shown in Figure I is recommended for new construction. Other enclosures shall be permitted to be used if they are shown to provide equivalent results and are of a size such that the internal volume of the enclosure, exclusive of the pyramid hood, shall not be less than 14.5 m3 (512 fe) nor greater than 36m3 (1272 fe), the floor area shall not be less than 6m2  (64 ft2) nor greater than 9m2 (97 ft2), and the maximum air movement within the enclosure complies with 4.3.

In the event of dispute, the results of tests conducted in an enclosure sized as shown in Figure I shall be final.

4.1.1   Enclosure walls

The walls of the enclosure should be constructed of concrete  masonry  materials  complying  with ASTM C90-2005. 8 The interior surface of the walls shall be painted flat black.

Alternative construction materials are acceptable for the enclosure walls provided the construction materials are capable of withstanding the high temperatures and open flame within the test enclosure.

4.1.2   Windows

For observation of the fire test, windows should be located in the walls and door, as shown in Figure 1. The exact location, size, and number of windows are not critical to test performance provided that  all windows  are air-tight.   It is suggested that the total surface area of the windows  should not exceed  1.8 m2
(20.0   ). Exercise  caution in selecting the window  materials  and construction  to withstand  the high
temperatures and open flame within the test enclosure.

4.1.3   Air intakes

Air intakes shall be provided at the base of two opposite walls. The total cross-sectional area  of the air intakes shall be 1.45 m2 ± 0.03 m2 (15.63 ft2 ± 35 ft2), and the intake areas shall be divided approximately equal. Figure 1 shows dimensions for the air intakes installed in walls with and without an access door. Air intakes shall not be permitted in either of the other two walls.

4.1.4   Access door

The enclosure shall contain an access door, typically constructed of steel, located as shown in Figure 1. The door shall be permitted to be located in any of the four walls. The sides and top of the door shall be adequately sealed to prevent drafts. The bottom of the door shall also be sealed to prevent drafts if it is not located in a wall containing an air intake.

4.1.5   Exhaust hood

A hood, formed as shown in Figure 1, shall be located on top of the enclosure walls. The area between the hood and the walls shall be sealed.

4.1.6   Collection  box

A 910 mm x 910 mm x 910 mm with tolerance of±15 mm on each side (36 in x 36 in x 36 in with a tolerance of 0.5 in on each side) stainless steel collection box shall be located on top of the exhaust hood as shown in Figure 1.


4.2 Exhaust duct

The exhaust duct connected to  the  collection  box  on  top  of  the  hood  shall  be  a 405  mm  ±  15 mm (16 in± 0.5 in) nominal inside diameter  steel pipe installed horizontally.

A variable-speed exhaust fan shall be located at the exhaust end of the duct. The exhaust duct shall be provided with instruments to measure gas velocity and temperature. A bidirectional probe or an equivalent measuring system shall be used to measure pressure in the duct. The probe shall be located in the exhaust duct at least 4.9 m (16ft) but not more than 13.7 m (45ft) from the centerline of the collection box. The minimum length between any bend and the probe shall be at least  10 times the inside diameter of the duct. The probe, shown in Figure 2, shall consist of a stainless steel cylinder with a solid diaphragm in the center that divides the probe into two chambers. The probe shall have a length nominally two times the outside diameter  of the cylinder with  a minimum  length  of 25.4 mm  (1.0 in) and  a maximum  length  of 51 mm
(2.0 in). The pressure taps on either side of the diaphragm support the probe. The axis of the probe shall be along the centerline of the duct. The taps shall be connected to a pressure transducer that shall be able to resolve pressure differences of 0.25 Pa (0.001 in of water). A bare bead, high-temperature Type K thermocouple,  0.51  mm  (20 mils)  in  diameter,  shall be  located  152 mm  (6 in)  upstream  from the
bidirectional  probe.



4.3   Air movement within the enclosure

The maximum air movement within the enclosure, with only the intake and exhaust openings open, the exhaust fan on, if applicable, and the burner off, shall not exceed 1 rnls (3.3 ftls), as measured by a vane­ type anemometer in the following areas:

a)   At the floor level where the burner will be positioned during the test

b)   1.5 m (4.9 ft) above the enclosure floor where the cable tray will be positioned during the test


4.4   Cable tray

A steel ladder cable tray, as shown in Figure 3, shall  be  used.  The  cable  tray  shall  comply  with NEMA VE 1-2002 or CSA Standard C22.2, No. 126.1-02. The rungs shall be attached to the inside of the side channels.

The tray shall be located so the burner flame will impinge on the cable midway between rungs.



4.5   Burner and mixer

The ribbon burner shall be a nominal 254 mm (10 in) strip- or ribbon-type propane-gas burner with an air/gas venturi mixer as shown in Annex A or IEC 60332-3-10.9

The burner shall be mounted on a stand and placed 20o ± 2o from the horizontal with the burner ports up (see Figure 3). The top of the burner shall be located 305 mm ± 25 mm (12 in± 1 in) above the base of the cable tray and parallel to the cable tray rungs.

A guide shall be attached to the burner or stand so the leading edge of the burner face can be accurately placed 76 mm ± 5 mm (3 in± 0.2 in) horizontally from the nearest surface of the cables.

4.6   Flovvnneters

A flowmeter shall be located in the propane line and in the air line feeding the burner to measure the flow rates of these gases during the test. The propane flowmeter shall be capable of measuring a flow rate of
230  cm3/s  (29  fe/h).  The  air  flowmeter  shall  be  capable  of  measuring  a  flow  rate  of  1360 cm3Is
(173 ft3/h). Measurements shall be accurate within 3%. A mass flow controller with an output that can be recorded should be used; however properly calibrated volumetric flow meters are also acceptable.


4.7   Supply air

The air supplied to the burner shall be compressed air, either bottled or supplied through a compressed air system. The air supply shall be filtered, when necessary, to eliminate contaminants that could affect the test results.


4.8   Propane

The propane gas supplied to the burner shall be equivalent to Propane HD-5 as specified in ANSI/ASTM Dl835-2003 or CAN/CGSB 3.14-06 (Grade 1). The gas shall have a nominal heating value
of  93.0  MJ/m 3    (2500  Btulfe).  The  temperature   of  the  propane   gas  shall  be  25  oc ±  5  oc
(77 op ± 9 °F).


5.   Test sample requirements



5.1   Cable sannples

Unless otherwise specified by the user, recognized testing laboratory, or the inspection authority having jurisdiction, the minimum conductor size construction for each cable design shall be tested to qualify all larger sizes using identical materials. Addition or deletion of a cable component or a change in material(s) shall constitute a new cable design, except that deletion of fillers or a strand separator shall not constitute a new cable design for power or control cable which has metal conductors.

Cable constructions shall consist of single-insulated conductors or multi-conductor cables within all applicable voltage classes, as follows:

a)   Multi-conductor  cables:  The  smallest  conductor  size  m  the  cable  design  with  the  fewest conductors, e.g., 2 conductor 18 AWG (0.823 mm2).

b)   Single-insulated conductors: The smallest single conductor in the cable design.


NOTE-Practical experience within the cable industry has shown that passing the test with the smallest conductor qualifies larger conductors within the same voltage class of the same cable design.'"



10 Notes in text, tables, and figures are given for infonnation only and do not contain requirements needed to implement the standard.

5.2 Tests required

Each cable design shall be subjected to two flame tests. A third and final test shall be performed if one of the first two tests results in a failure.


6. Flame test procedure


6.1 Cable mounting

The length of each cable specimen or each cable bundle shall be 2.4 m ± O.I m (8 ft ± 0.3 ft). Depending on the outside diameter of the individual cable, the test specimen shall be either an individual length or a bundle of individual lengths. The specimens or specimen bundles shall be centered between the side rails in a single layer. The lower end of each specimen or specimen bundle shall be located not more than I 00 mm (4 in) above the bottom end of the cable tray. Each specimen or specimen bundle shall be separately attached to each rung of the cable tray using one wrap of a copper or steel wire tie not larger than I4 AWG
(2.08 mm2).

6.1.1 Cables smaller than 13 mm (0.51 in)

For cables smaller in diameter than 13 mm (0.5I in), the specimens shall be grouped into untwisted bundles (nominally circular) as specified in Table I or Table 2. The bundles shall be spaced one-half bundle diameter apart on the cable tray as measured at the point of attachment to the cable tray.

NOTE-For the purposes of this standard, a cable is any single-insulated conductor or assembly of insulated conductors. The cable OD is the outside diameter of a cable including any overall jacket or sheath.



6.1.2   Cables 13 mm (0.51 in) and larger

For cables 13 mm (0.51 in) in diameter and larger, the individual specimens shall be attached to the cable tray with a separation of one-half cable diameter or 15 mm (0.6 in), whichever is less. The tray loading shall comply with Table 3 or Table 4.

NOTE-For the purposes of this standard, a cable is any single-insulated conductor or  assembly  of  insulated conductors. The cable OD is the outside diameter of a cable including any overall jacket  or sheath



6.1.3   Flat cables

For flat cables, the equivalent cable diameter shall be calculated using the following formula:

D = 1.128.(Tw)^0,5   (1)

where

D   is the calculated cable diameter, mm (in)
T   is the thickness or minor axis ofthe cable, mm (in)
W   is the width or major axis of the cable, mm (in)

For ribbon cables, the spacing between adjacent cables shall not be less than 3.2 mm (1/8 in). The full width of the tray may be used.

6.2   Test procedure


6.2.1   Cables and cable tray

The cables mounted on the cable tray shall be conditioned at a temperature of 25 oc ± 5 oc (77 °F ± 9 °F) for at least 3 h immediately before commencing the test. The dew point of the air inside the enclosure does not need to be measured.

The prepared cable tray shall be positioned vertically in the enclosure (as shown in Figure 1) so that the rungs of the cable tray are parallel to the walls containing the ventilation openings. The lower end of the cable specimens shall be positioned so that the bottom of the specimens is at least 203 mm (8 in) below the top of the burner. The cable tray shall be firmly fixed in position.

6.2.2   Exhaust duct flow rate

The initial volumetric flow rate of air through the duct shall be 0.65 m3/s ± 0.05 m3/s (23 ff/s ± 1.8 ff/s). The volumetric flow rate of the air in the duct shall be calculated from Equation (2) (Crocker [Bl]). Once the initial flow rate has been established, the fan speed shall not be reduced. The fan speed shall be increased if the flow rate falls below the initial set value to maintain the initial volumetric flow rate.



6.2.3   Burner

The burner shall be ignited, and gas flows shall be adjusted to the values specified below. The burner, at an angle of 20° from the horizontal, shall be positioned in front of the cable tray and 75 mm ± 5 mm (3 in± 0.2 in) from the nearest cable surface as shown in Figure 3.

The propane flow rate shall be 220 cm3/s ± 8 cm3/s (28 fe/h ± I fe!h) when corrected to standard temperature and pressure 20 °C, I 0 I kPa (68 op, I4.6 psia). This propane flow rate provides a theoretical heat output of 20 kW (70 000 Btu/h). The actual heat output may be less, due to incomplete combustion of the propane at the burner.

When propane other than the grade specified in 4.8 is used, the propane flow rate shall be adjusted to maintain the 20 kW (70 000 Btu/h) heat input. In the event of dispute, the test results obtained using the propane specified in 4.8 shall be final.

6.2.4   Airflow and air temperature


The airflow rate shall be 1280 cm3/s ± 8 cm3/s (163 fe/h ± 10 ft3/h) when corrected to standard temperature and   pressure.   The   temperature   of   the   air   feeding   the   burner   shall   be   25   oc  ±   5   oc
(77 °F ± 9 °F). The dew point of the air shall not be greater than 0 °C (32 °F).

The temperature of the ambient air entering and inside the enclosure shall be greater than 5 oc (41°F). The dew point of the air does not need to be measured.

6.2.5   Test duration

The burner flame shall impinge on the specimens for a continuous period of 20 min.

At the end of the 20-min period, the burner flame shall be extinguished and the cable fire (if any) allowed to self-extinguish. The time of after bum shall be recorded.

6.2.6   Supplemental information

During the flame exposure, visual flame height may be recorded for informational purposes. Pictures or video of the flame propagation testing may be made for informational purposes.

7.   Test evaluation



7.1   Evaluation of damage

After burning has ceased, the cables shall be wiped clean, and the maximum extent of cable damage shall be determined. Soot that can be removed with a cloth shall be ignored. It is not necessary to require the cable tray assembly to cool to room temperature before evaluating flame propagation or taking measurements of cable damage. However, proper safety precautions shall be taken.

7.1.1   Cable char damage

The limit of charring shall be determined by pressing against the cable surface with a sharp object. In places where the surface of the cable changes from a resilient to a brittle or crumbling surface, the limit of charring has been identified. Cable damage shall then be documented by measuring the distance of the charred height on the most centrally located specimens above the horizontal line from the lower edge of the burner face to the nearest 25 mm (1 in).

7.1.2   Non-cable char damage

Certain cable constructions may not "char" upon exposure to flame due to the characteristics of jacket/insulation compounds used. For these constructions, the limit for the affected cable damage shall be defined as the point where the overall diameter is visibly reduced or increased. Affected cable damage shall

then be docwnented by measuring the distance from this point to the horizontal line at the lower edge of the burner face to the nearest 25 mm (1 in).

In  addition,  other  cable  degradation  evidence  such  as  melting  or  blistering  maybe  recorded  for informational  purposes.


7.2 Performance criteria

The sample shall have complied with this standard and met the performance criteria if the length of cable damage does not exceed 1.5 m ± 25 mm (4.9 ft ± 1 in), when measured in accordance with 7.1, in two tests.


7.3   Test report

A Test Record Data Sheet shall be completed for each flame test. The following information shall be recorded for each test:

a)   Date of testing

b)   Location of testing

c)   Test nwnber

d)   Test leader/supervisor

e)   Test observer(s), if any

t)   Inside dimensions of enclosure, if not in accordance with this standard

g)   Cable manufacturer's name

h)   Cable identification/type and catalog nwnber

i)   Complete description of the cable construction, including outside diameter

j)   NEC, CEC, or MEC type designation, as applicable

k)   Nwnber of cable specimens or bundles in the cable tray

I)   Temperature of air outside enclosure

m)   Temperature inside enclosure prior to starting test

n)   Airflow rate at the floor level

o)   Airflow rate at 1.5 m (4.9 ft) above the floor

p)   Propane flow rate

q)   Airflow rate into the burner

r)   Airflow rate through the exhaust duct

s)   Maximwn length of cable damage

t)   Time of after burn

u)   Test results-pass or fail

v)   Comments

AnnexA (normative)
Burner and mixer information

The burner number  1OL1155 and venturi mixer number  14-18 for use in this standard is as shown in Figure A. I.



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