7/29/2019 Lightning Protection Sizing

1/1

PROJECT : -

CLIENT :-

CLIENT'S CONSULTANT :-

CONTRACTOR :-

i) Input Data :-a) Dimensions of Building / StructureLength of the Building L = 60.00 m

Width of the Building W = 28.00 m

Height of the Building H = 23.00 m

b) Lightning Flash Density & Weighing FactorsNumber of Thunderstorm Days / Year N = 100 No. of Days / Year

Li htnin Flash Densit (Flashes to Ground /km2/ ear) Ng = 9.2 Nos./km

2/ ear

Weighting Factor A ( Use of Structure ) A ( Refer Table 1A of IS 2309 ) = 1

Weighting Factor B ( Type of Construction ) B ( Refer Table 1B of IS 2309 ) = 0.8

Weighting Factor C ( Content of Consequential Effects ) C ( Refer Table 1C of IS 2309 ) = 1

Weighting Factor D ( Degree of Isolation ) D ( Refer Table 1D of IS 2309 ) = 0.4

Weighting Factor E ( Type of Country ) E ( Refer Table 1E of IS 2309 ) = 0.3

ii) Calculations :-

Overall Multiplying Factor = AxBxCxDxE = 0.096000

= 0.006526

ie 6.5260E-03

iii) Maximum Acceptable Overall Risk Factor:-

= 0.000001ie 1.000E-06

iv) Result / Conclusion :-

>

Calculations (As per Clause 12.2.3 of IS-2309):-

Base Area of Structure Ab = = 1680 Meter2

Perimeter of Structure P = = 176 Meter

i) For Base Area (Ab) < 100m2

a) Number of Down Conductors Required = = 1 Nos

ii) For Base Area (Ab) > 100m2

b) Based on Base Area of Structure:-

= = 6 Nos

c) Based on Parimeter of Structure:-

= = 6 Nos.

Hence, Required Number of Down Conductors = 6 Nos.

Rev. Date Drg/Doc. No. Reviewed ApprovedR0

A) CHECK FOR NEED OF PROVIDING LIGHTNING PROTECTION

PACKAGE4 INDOOR SUBSTATIONS-NEW & MODIFICATIONS

OCP

Uhde

Spie Maroc

LIGHTNING PROTECTION CALCULATION FOR PJ-TPP BUILDING

( REFERENCE : IS 2309 )

Description / ParameterSymbol / Formulae /

ReferencesValue Unit

( Refer the Relevant Layout

Drawings of the Building /

Structure )

( Refer Fig. 1 of IS 2309 )

( Refer Clause 8.1.2 of

Collection Area ( Refer Clause 8.1.2 of IS 2309 ) Ac =(L x W) + 2 (L x H) +

2(W x H) + 3.14 H

2 = 7389.06 Meter2

Probable Number of Strikes to Building / Structure per Year (

Refer Clause 8.1.2 of IS 2309 )P = Ac x Ng x 10

-6times/year = 0.067979 Times per year

( L x W )

Overall Risk Factor Calculated Rf-C =Overall Multiplying

Factor x P

Maximum Acceptable Overall Risk Factor Rf-A( Refer Clauses 8.1.3 &

8.1.6 of IS 2309 )

Since Overall Risk Factor Calculated Maximum Acceptable Overall Risk Factor

Hence, Lightning Protection is Required.

B) CHECK FOR ADEQUACY OF NUMBER OF DOWN CONDUCTORS

2(L+W)

For Ab < 100m2

Number of Down Conductors Required 1+(Ab-100)/300

Number of Down Conductors Required P/30

Note:- The Number of Down Conductor should be at least the smaller between b) & c) (as per clause 12.2.3b of IS-2309)

REVISION

DETAILS Remarks Prepared

First Submission