Calculate \(\beta\) - *local heat loss coefficient* according to rule *11.3.3*
of Minenergo Order 325.
*Local heat loss coefficient* is used to increase normative heat loss
of pipe by taking into account heat loss of fittings (shut-off valves,
compensators and supports). This coefficient is applied mostly as a factor
during the summation of heat losses of pipes in pipeline leveraging
formula 14 of Minenergo Order 325.

## Arguments

- laying
type of pipe laying depicting the position of pipe in space:

`air`

,`channel`

,`room`

,`tunnel`

,`underground`

.

Type:

`assert_subset`

.- d
internal diameter of pipe, [

*mm*]. Type:`assert_double`

.

## Value

Two possible values of \(\beta\): `1.2`

or `1.15`

depending on
pipe laying and its diameter. Type: `assert_double`

.

## See also

Other Minenergo:
`m278hlair()`

,
`m278hlcha()`

,
`m278hlund()`

,
`m278insdata`

,
`m278inshcm()`

,
`m278soildata`

,
`m325nhl()`

,
`m325nhldata`

,
`m325testbench`

## Examples

```
library(pipenostics)
norms <- within(m325nhldata, {
beta <- m325beta(laying, as.double(diameter))
})
unique(norms$beta)
#> [1] 1.15 1.20
# [1] 1.15 1.20
```