How to calculate the lightning protection

This article is intended to introduce you to the answer to the question about how to calculate the lightning protection line. I hope you can learn more after reading it.

How to calculate the lightning protection

1Using the main structural steel bar as the lightning protection and down-line engineering quantity calculation:

When calculating the amount of steel used as the lightning protection down conductor of the main structure, it should be calculated according to the design requirements. When the design requires the use of two main ribs, the engineering quantity should be calculated according to the total length of the main ribs used.

Example: A building is 85m high. There are 6 buildings in this building that use the main steel bars as the lightning protection down line. Each place requires the use of two main bars to calculate the amount of work:

The down-line engineering quantity is 85×6×2=1020m

2 The design uses the basic steel bar as the grounding grid, and the calculation method of the engineering quantity:

Its engineering quantity calculation method:

(1), the main steel bar is used to extend the length of the meter L and multiplied by the design requirements to use the number of base bars n: L × n --------- (a) full length of the steel bar

(2), the total length of the used steel bars is divided by 6 (one welding at an average of 6 m) (L × n) / 6 -------- (b) Connection

(3), the length of the single-strength steel is multiplied by the number of roots minus one and then divided by 6 (one bridge between two main ribs per 6m on average)

L × (n-1)] / 6 -------- (c) Span (4), (b) + (c) = (d) -------- total welds

Note: In the above formula, 6 is the average length of the single length of the building steel bar. The actual average length is different and can be converted. The span of the bridge can be converted if required by the design.

Example: The design requires the use of two main ribs as the grounding grid, with a single length of 350m and a 4m span. Try to calculate the total weld: d=b+c

=(L×n)/4+[L×(n-1)]/4 =(350×2)/4+[350×(2-1)]/4=175+88=263(处)

3 The grounding resistance test disconnecting plate designed in the lightning protection down conductor of the building can be used according to the grounding jumper socket. Each test disconnecting plate is one place, and the connecting bolts are not charged. 4 grounding commissioning calculation

According to the specification:

a. The single-group grounding electrode shall be tested once or not, and the test shall not meet the requirements. After the grounding electrode is added, the test may be carried out once, which may be counted once, that is, according to the number of tests.

b. The grounding grid is connected by multiple grounding poles. It can be tested according to the network length of 50m. If it is less than 50m, it should also be calculated according to the design of the specified network length. After calculating the commissioning unit according to the network length, no matter how many grounding poles, the commissioning cost is no longer calculated. The total length of the grounding grid is based on the maximum peripheral length, and the length of the grid is not counted.

Example: The grounding grid of an engineering is as follows (the design of the network length of the test unit is undetermined), and the number of commissioning units (systems) is calculated:

Net length (peripheral length) = (30 + 90) × 2 = 240m Test unit = network length / 50 = 240 / 50 = 4.8

The grounding grid of this project can calculate the commissioning cost according to 5 systems.

c. When using the building foundation steel bar as the grounding net, apply the grounding device to debug the sub-project. The number of debugging systems shall be based on the number of grounding resistance test disconnecting plates required by the design. If there is no test disconnecting plate, refer to the above b method. Calculate the test unit and apply the grounding pole to debug the sub-item