If a lighting manufacturer, not a lamp manufacturer, were to use PPFD as a specification for a specific fixture/lamp combination they’d have to be compelled to embody all of the subsequent data for the user to properly interpret the knowledge being given:
- Provide the peak from that the mensuration was taken.
- Provide multiple locations across the light footprint at significant points leaving interpretation of consistency of intensity and footprint limitations.
- Provide multiple sets of PPFD measurements at completely different heights.
To publish in an exceedingly PPFD price numerous concerns with this approach would be:
1.Measurements should be soft on reflectors in situ to attain correct results.
2.For HID lamps since the lamps area unit sold cut loose the reflectors there may be many alternative combos of lamps and reflectors. Any measurements taken have to be compelled to be specific to a specific lamp/reflector combination.
3.At the shut height that grow lamps area unit used their light distribution patterns won’t modification in an exceedingly regular expected manner. the employment of a reflector within the style needs that a definite minimum mensuration distance is employed for values to stabilize and act with an expected regularity for varied heights. This height in several cases are bigger than the standard height used for an inside grow, however would possible be smart for a greenhouse supplemental application. essentially we tend to area unit pertaining to relationship of sunshine Intensity as a operate of 1/d2, wherever d is that the mensuration distance from the sunshine supply. till this bound height is achieved, you’ll not see measured values following this rule the least bit.
4.As for LED panels, these measurements won’t stabilize till a height is reached that the beam patterns of the LEDs have latticelike enough to be somewhat consistent, each with relevance intensity and mixture of various LED lighting wavelengths.
5.Interpreting the results of overlapping light from adjacent lamps in multiple lamp systems may be a tough task, however would be necessary to see verity amount of sunshine intensity at any explicit purpose.
6.It will be possible still take some field experimentation with correct mensuration instrumentality and completely different configurations of the lamps to come back to the optimum lamp placement, significantly in an exceedingly multiple lamp system.
PPF and PPFD actually have their place once discussing about grow lamp output values and the way those values could then be measured within the field. However, there will exist inconsistencies on however lamp and sensing element makers use these terms and for the common gardener UN agency could lack advanced degrees in Physics and Engineering, these don’t seem to be aiming to be terms they’ll simply come back to grips anyway. per se we tend to felt introducing another methodology, that was easier to grasp, would be so as.