Field Guide
Offline plumbing and heating tools.
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Radiator balancing records
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Pipe offset
Set out two bends to shift a pipe onto a parallel line.
Measurements
mm
°
Copper pipe size
Bend settings
mm
Estimated mark spacing
Handlebar crossover
Bridge an obstruction with four bends.
Measurements
mm
Centreline to centreline.
mm
Straight across the top.
Copper pipe size
Bend settings 30°
mm
Leave blank to use the estimate for this pipe size.
Four bend marks
Measure all four marks along straight copper from mark 1.
Straight pipe · schematic
- Finished span
- Pipe used by bridge and bends
Bending guide
Leave pipe beyond both outer marks for gripping and connections. Use the same angle for all four bends and keep the pipe in one plane.
Check the pivot-pin reference
These marks assume your chosen point on the pivot pin lines up with where the curve starts. Try the sequence on scrap with your bender and check the finished rise and straight bridge length before using it on the job.
Room BTU calculator
Estimate how much heat a room needs on a cold day.
Measurements
m
m
m
m
m²
Add the lengths of walls facing outdoors. Include window and glazed door area separately.
Construction and design temperatures
°C
°C
W
Radiator water temperatures
°C
°C
°C
Estimated room heat loss
Quick estimate for a rectangular room. Confirm sizing with a room-by-room heat-loss survey before buying equipment.
How it’s calculated
Heat loss through each surface uses its area, assumed U-value and the temperature difference. The estimate treats the selected floor and roof as exposed to outdoor temperature and adjoining heated spaces as having no heat loss. Air loss uses the room volume and air changes per hour.
Radiator output uses a generic panel-radiator correction of (ΔT ÷ 50)1.3. Check the manufacturer’s data for your model.
Room-by-room heat loss
Survey each heated room to estimate the house’s heat loss on a cold day.
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House heat loss
0 kW
Saved rooms
Add your first room to start the survey.
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Add room
Calculation method and limits
Fabric loss uses area × U-value × temperature difference. Ventilation uses room volume × effective air changes per hour × 0.33 × the indoor–outdoor temperature difference. The house figure adds the saved room losses. Enter each external or unheated boundary once.
Use effective U-values and adjacent temperatures from the survey, including for floors against the ground. This is a design estimate with manual inputs. It does not implement the full BS EN 12831 or MCS compliance method.
Boiler & cylinder sizing
Check the heating load and size hot water for your busiest period.
Space-heating load
Compare this load with the boiler’s heating output at your design temperatures. Check how low the boiler can modulate for milder days.
Open heat-loss surveyHot-water demand
°C
°C
L/min
Add the mixed flow rates of outlets you expect to use together.
L
Add the litres for showers, baths and taps used before the cylinder can recover.
°C
min
Use the specified storage temperature for the system. The outlet temperature above is the temperature after mixing.
Combi hot-water output
Use the heating and hot-water figures separately. For a stored system, check how the controls schedule cylinder recovery alongside space heating.
Natural gas tools
Meter gas rate and low-pressure copper pipe sizing in UK units.
Timed meter reading
s
MJ/m³
Enter the volume difference over the timed test in the selected meter units.
Gas rate and gross heat input
Gross input uses measured flow × gross calorific value ÷ 3.6. The default is a reference value. Follow the appliance instructions and use their stated test basis.
Meter-to-appliance route
Add each section in order. Enter the combined maximum gross input of every appliance fed by that section. Check each appliance route separately.
Estimated route pressure drop
Low-pressure natural gas and smooth copper only. Check the actual pipe bore, fitting allowances, appliance inlet pressure and current requirements before relying on the result.
Calculation method
Uses pressure-loss figures verified against BS 6891 Annex A, Table A.1. Loads use the next published row when between rows. Each section is rounded up to 0.01 mbar before the route total, as in the worked example.
Use Table A.5 or the fitting manufacturer’s applicable data for equivalent lengths. For a tee, check the direction of flow and use the largest connection size on the fitting. Recheck allowances if you change a pipe size.
BS 6891 · gas pipework standardFor design and checking by appropriately qualified Gas Safe registered engineers.
Water flow rate
Size heating flow or measure tap pressure and delivery.
Measurements
kW
°C
°C
0.0 s
L
s
Start once the tap runs steadily. Use a heat-safe jug for hot water.
Where to connect the gauge
Required heating flow
Radiator balancing
Set design flow targets and keep a record of valve adjustments.
Radiator worksheet
Save a room in Room-by-room heat loss to start.
Target flow
Measure both pipes with contact probes after the system settles. Make small adjustments and recheck earlier radiators because changing one branch can affect others.
Pipe & fitting identifier
Use the outside diameter, pipe markings and the shape of the joint together.
Measure the bare pipe
mm
Likely matches
Recognise the connection
Clips, falls & head
Clip spacing
m
mm
Supports for this run
Includes a clip at each end. Check the pipe system’s support and expansion instructions. For gas pipework, use the support intervals specified for gas installations.
Why support spacing matters
Supports limit sag and movement. On a waste run, a dip between clips can hold water even when the two ends have the right fall.
Round the number of gaps up so each gap stays within the maximum spacing, then add one for the clip at the far end. A 3 m run with a 1,200 mm maximum needs three gaps and four clips, spaced 1,000 mm apart.
Support spacing sourceWaste and gutter falls
m
mm/m
Fall over the run
The result is the vertical drop from the high end to the outlet. Measure the run horizontally between those points.
How to work out fall
Multiply the horizontal run in metres by the gradient in mm/m. At 18 mm/m, a 3 m waste run drops 54 mm.
For a ratio, convert the run to millimetres, then divide by the second number. At 1 in 600, a 5.25 m gutter drops 8.75 mm.
If you already know the drop, divide it in millimetres by the run in metres to get mm/m. A 36 mm drop over 2 m gives 18 mm/m.
Why the fall and run length matter
Gravity carries water and waste along the pipe. A shallow stretch, dip or backfall can leave water and debris behind. Check the fall between supports as well as at the ends.
Pipe size, run length and ventilation affect how air moves when a fixture empties. Pressure changes can pull water out of the trap, which lets drain smells through. If a branch falls outside the preset’s conditions, check the design for sizing and ventilation before choosing a gradient.
For 32 mm basin and bidet waste, the two examples show how the upper gradient changes with run length. The 1 m example uses 40 mm/m. At 1.7 m, the range is 18–22 mm/m. For another length, enter the gradient specified for your branch under “Enter your own fall”.
Setting out a gutter
Choose the outlet position first. Measure from the high point to that outlet. With a centre outlet, calculate the drop on each side using its own run.
Mark the high and low points and use a taut line or laser to set the intermediate brackets. Check for dips, then run water through to check that it reaches the outlet and the joints stay dry underneath.
The 1 in 600 preset gives a gentle fall towards the outlet. Use the fall specified for the gutter system. Roof area, rainfall, gutter profile and outlet layout determine how much water the system can carry.
Open gutter & downpipe sizingGuidance and scope
The presets cover common above-ground arrangements. WC branch limits depend on outlet size, how many WCs share the branch and how it is ventilated. Buried drains use different sizing and gradient criteria. Check the requirements where the work is being done.
Approved Document H · EnglandHydrostatic head
m
For an open tank, measure vertically from the water surface to the point where you want the pressure.
Where to measure
Static water pressure
Assumes still fresh water. Pressure at a running outlet also depends on flow and losses through pipes and fittings.
Pipe volume & dosing
Calculate water content and scale the product dose on the label.
Measurements
mm
m
L
mL
L
Water volume and dose
Use the actual inside bore. Add the water content of other pipe runs, radiators and equipment in Other system volume. Enter the label dose for the product you’re using.
Drain invert levels
Set out the bottom inside edge of a pipe at each point down the run.
Measurements
m
m
mm/m
m
Where to measure
Downstream invert level
All levels use the same datum as your upstream measurement. Use the gradient specified for the drain.
Pipe cut length
Work out the straight pipe length between two socket fittings.
Measurements
mm
mm
mm
mm
mm
Cut length
Measure both fittings along the pipe axis. Use the manufacturer’s insertion depth and any required expansion allowance. The numbers shown initially are examples.
Gutter & downpipe sizing
Compare the runoff reaching one outlet with the capacity of a matched system.
Measurements
m²
mm/h
L/s
Use effective area and design rainfall for the job. The 75 mm/h figure is an example.
Runoff and capacity
The FloPlast presets use published design capacities for straight runs with matching downpipes. Use a manufacturer’s adjusted figure for angles, long runs or a different layout.
Published gutter capacity tablePump head
Estimate the duty point from the resistance of the circuit at your design flow.
Measurements
L/min
m
m
Pa/m
kPa
m
Compare with a pump curve
m
For heating, include both flow and return on the highest-resistance circuit. Use pipe and component loss data at their design flows.
Required pump duty
This is a water estimate based on the resistance you enter. Use the pump curve at the same flow and speed setting. In a closed circuit, building height is excluded from circulating head.
Measurements
How this works
Technical referenceLow-carbon steel bending
Set out a single bend or a two-bend offset using your RIDGID former.
Measurements
mm
Use a verified radius for your former and pipe, or measure a trial bend after releasing the load. If you measured the inside radius, add half the actual pipe outside diameter.
°
mm
Bend set-out
Use a matching former and support positions for your exact bender, pipe size and wall series. Check your marking reference and springback on scrap from the same pipe.
How this is calculated
Setback is the distance from the theoretical corner to the start or end of the curve. It increases with both bend angle and radius. Arc length is the developed length along the centreline of the curve.
For an offset, the two curves use part of the rise. Divide the remaining rise by the sine of the angle to get the straight diagonal between the curves. A larger radius leaves less room for that straight. The theoretical corner spacing is a geometry reference. Transfer it to your bender using your trial piece.
RIDGID hydraulic bender manual, Specifications (printed page 5)
Full crossover
Mark out a three-bend crossover.
Measurements
Copper pipe you’re bending
Bend pattern
mm
Include insulation. Assumes both pipe centrelines start at the same height.
mm
mm
Bend settings
mm
mm
mm
mm
Leave fields blank to use the defaults. Enter zero width to check the crown only.
Three bend marks
Mark 1 is the peak over the crossing. For a fixed pipe end, see the allowance below.
How this is calculated
Pull mark 1 to 60°. Roll the pipe half a turn along its length for mark 2 and keep that roll for mark 3. Pull both outer bends to 30°. Keep all three bends in one plane. On scrap copper of the same size, check where each bend-centre mark lines up on your former and verify the finished angles and clearance. Monument former angle markings
The centre bend is twice the outer angle so both tails return to the original pipe line. The mark spacing includes one straight slope and half the arc length of each adjacent bend.
With a width entered, the tool treats the obstruction as a flat-topped box. It checks to the side of that box by an extra pipe radius plus the requested gap and allows for the saddle dropping away from the peak. The straight slope is extended for this check, which gives a conservative estimate where the real pipe rounds into the tail.