ISODRAFT Reference Manual

Function:	Defines the maximum rate of fall allowed in a pipeline before it is shown as a skew on the isometric plot.
Description:	Amounts of fall less than the current fall limit are shown by a wedge-shaped symbol on the pipe, together with a note giving the rate of fall. The wedge-shaped symbols are known as fall arrows. Amounts of fall greater than the current limit are shown as boxed skews. The user can change the limit, and the units in which it is expressed.
Figure 2:4. Different ways of showing falling lines.
	The default accuracy to which ISODRAFT will report the fall is as follows: • Degrees to the nearest half degree • Ratio to the nearest 1 up to 30; to the nearest 5 above 30 • Percentage to the nearest 1% • Grads to the nearest half grad • Metric inclination to the nearest 10mm per metre • Imperial inclination to the nearest 1/16” per foot
	Note: That if the slope is less than 1:500 (or its equivalent in degrees, etc) the fall note will not be output. The user can specify different accuracy values for reporting the fall using the ACCURACYLEVEL value command (where value can be zero, 1 or 2). The accuracies the user can specify are:

		value (for each representation)	0	1	2
		degrees	default	0.1	0.01
		ratio	default	1 always	1 always
		percentage	default	0.1	0.01
		grads	default	0.1	0.01
		metric	default	1mm/m	0.1mm/m
		imperial	default	1/16”/10’	1/16”/100’

If the user sets an accuracy level and then wants to go back to the default settings, the user must give an appropriate ACCURACYLEVEL command with a value of zero. If the fall units are specified but the value of the fall limit is omitted, the following default values will be used. These correspond to approximately the same slope:

	FALL DEG	will default to	FALL DEG 5	i.e. 5 degrees
	FALL RAT	will default to	FALL RAT 11	i.e. a ratio of 1:11
	FALL PER	will default to	FALL PER 9	i.e. a slope of 9%
	FALL GRA	will default to	FALL GRA 5	i.e. 5 grads
	FALL MET	will default to	FALL MET 80	i.e. 80mm per metre
	FALL IMP	will default to	FALL IMP 1	i.e. 1/16 inch per foot

	The overall default setting, if no fall units or limit are specified, is FALL DEG 5. Where a falling section includes an in-line component, such as a Valve or Reducer, the FALL message will appear only once, against the first section of the slope. Where a falling section incorporates a Tee, the FALL message will be shown twice, on both sides of the Tee.
Figure 2:5. Falls in sections of pipe containing components.
Examples:	FALL RATIO 20	Sets fall limit to 1:20
	FALL RATIO	Resets fall limit to ratio default of 1:11.
	FALL PERCENT 2	Sets fall limit to 2%.
	FALL PERCENT	Resets fall limit to percentage default of 9%.
	FALL OFF	All falls shown as boxed skews; fall symbol not used at all.
	FALL 1.4 DEG	Sets fall limit to 1.5 degrees.
	FALL RAT 1:40	Sets fall limit to 1:40.
	FALL PER 2.7%	Sets fall limit to 3% (to nearest per cent).
	FALL GRAD 1.6	Sets fall limit to 1.5 grad.
	FALL MET 30	Sets fall limit to a metric incline of 30mm/m.
	FALL IMP 5/16”	Sets fall limit to an imperial incline of 5/16” per ft.
	FALL MET 30 ACC 1	Sets fall limit to a metric incline of 30mm/m with a reporting accuracy of 1mm per metre.
Related Commands:	ANGLEACCURACY FALLSKEWS SKEWBOX ZEROLENGTHSKEWS
Command Syntax:
>- FALLinglines -+- DEG --------.                  |              |                  |- RATio ------|                  |              |                  |- PERcentage -|                  |              |                  |- GRAds ------|                  |              |                  |- IMPerial ---|                  |              |                  |- METric -----+- value --.                  |              |          |                  |              |          |- ACCuracylevel value -.                  |              |          |                       |                  |              ‘----------+-----------------------|                  |                                                 |                  ‘- OFF -------------------------------------------+->
Querying:	Q FALLinglines Q OPTions