Sunday, May 29, 2016

Attic Ladder Safety Innovation, 2016

Captioned photos that follow are from web album Innovations In Attic Ladder Safety . The photos are in reverse chronology from Spring 2016 to Spring, 2015. Innovation never ends. I hope mine is speeding up.

The album and this post are in service of a consensus Year-2018 revision of the International Energy Conservation Code, Paragraph 402.2.4. My campaign for the revision began seven years ago, twice missing once every three year revision cycles. My web site R5 Portals  collects all of the campaign information. This blog post will be duplicated in a first installment for a new page at the r5portals site, Innovations In Safety .

2015 IECC states: "Access shall be provided to all equipment that prevents damaging or compressing the insulation. A wood- framed or equivalent baffle or retainer is required to be provided when loose-fill insulation is installed, the purpose of which is to prevent the loose-fill insulation from spilling into the living space when the attic access is opened, and to provide a permanent means of maintaining the installed R-value of the loose-fill insulation."

I believe we need much more access provision, for safe work and achievement in attics. Reaching far, my proposal asks this: "The entry to an attic space at a portal shall have a surround of an ample raised floor that does not diminish insulation value. Flooring shall protect insulation against trampling while giving safe passage, to all attic electrical service points including fans, lights and junction boxes. Junction boxes not accessible from heated space shall be raised above insulation and flooring levels, or where this has failed, shall be flagged as a decked service point. Accessible service points will include static vents that require periodic cleaning. Where there is burial in insulation at a service point, insulation must be of batt form, tolerant of the displacement."

Please judge what compromise here, serves best. 
A near step-through occurred where an inspector toppled from this fragile OSB rim. Such minimal yet expensive structure seems to be prescribed in 2015 IECC. The installed cost of a simple factory-built access plug and surround might be less than that of a plunker and drywall edging. Step through repairs are expensive and often imperfect, and such cost is nothing compared to consequence of injuries, that do happen. Years of energy waste in trampled insulation cancel savings, and those are pocketed by a builder.

Without new flooring requirements, a drop-down ladder here would be no safer. Cheapest ladders are framed for 2x4 floor joists, then if there is not mandatory flooring, again barricaded against initially-deep loose fill, by a similar OSB skirt.

The tentatively-approved 2018 revision of IECC R402.2.4 makes no change of rules that result in the dangerous construction in the photo above, where a drywall plunker would still need an R38 batt gob in Oregon, or an R49 gob in Minnesota. The tentative new rule just allows that, if a drop down ladder is installed, it may be about R8 (U<= 0.10). Present construction endangering workers and an obstacle to good attic weatherization, is not addressed. In debating best rule change that then considers worker safety, we must understand what is possible.

Please see that my IECC proposal is a large compromise of all I find necessary in my work, for my safety, and to guard against liability should a customer be injured. I hope that I can prevent an accident by offering always at no added cost, every safety feature I imagine.

This attic in action is served by a Fakro LTK 22/47 drop-down ladder set at safe 60° angle. 2x10 rough opening sides are suspended from 2x10 composite beams bearing upon hallway walls. A 2x4 safety pole is rigidly attached to floor framing and roof joists. A lighted switch on a safety pole grip empowers bright lighting while a worker is still securely standing on the ladder center section. Footing on the ladder top section is more tricky, then with a hand advancing to bear weight transfers, on  safety pole grips.

An added hinge in the center section is essential to convenient and compact deployment. Bend at the added hinges, and tug straight down. Without the added hinges, the deploying ladder would not clear the ladder frame. Leveler legs give best protection against floor scuffing. Soft-rubber leveler legs also resist the scary phenomenon of "kickout", where a bottom section may suddenly transfer upright if one leans forward, midway up the steps.

This ladder is directly over a garage door. While deployed, a 3-way switch below for attic lighting, acting as SPDT, overrides the garage door operator. Safety pole hand grips are fixed to a truss element.

I modify "Recovery" ladders by Calvert USA, with safer broad top steps. The new step gives match of ladder step pitch, for the 10" distance to the raised attic floor. Probing down with a foot, one will not be tricked by weight bearing on tops of ladder step sides or the top edge of the door. In ladders I prefer, by Fakro, Calvert USA and MidMade, door springs operate entirely upon the ladder door. There is little in the "hole" to snag a person or object carried.

It generally works out that a ladder acts parallel to floor and roof joists, with egress in attic at roof peak. Hold on while moving about the safety pole. Guide yourself by the safety pole. Rails about the hole obstruct, raising new dangers, and I rarely build them.

Here a drywall plunker hole to the attic, replaced by a Fakro LTK 22/47 ladder, is not patched out. A hoist via that opening is offered, where some items appropriately stored in attic conditions, might be very heavy. The LTK ladder has 300 pound rating, but there is more danger in falling while carrying a clumsy object, than in some breakage of the ladder. Observe neat lines and near-invisibility of hatches edge-dressed with flexible grout.

Here is a hoist concept for attic storage of clumsy objects.

A loading hatch might rarely be used. It is closed by a prototype of an R6 factory-built plug. Where usage involves access from the attic via a parallel ladder, added insulation might be placed under the lid, upon the plug, saving perhaps $1 per year of heating cost. Don't spend more than $10 for the pillow!

Thursday, May 12, 2016

Luminaire Luminance Definitions

Consider the mindfulness of LED downlight luminaire manufacturers to be considerate of those who might have diode glare burned into their short-term vision, seeing dots. The measure of this glare is luminance , computed from measured (claimed) lumens output of diodes, and meaningful unit area. Areas that seem convenient are Diode Area, the sum of diode surface areas, and Array Area, an area in which the array of diodes is confined.

The Wikipedia discussion of luminance includes statement that: The sun has luminance of about 1.6 times ten-to-the-ninth candela per sq meter at noon. ("Luminance". Lighting Design Glossary. Retrieved Apr 13, 2009.) 

At the outset here, relate the glow of an LED diode maybe-stared-at, to the glow of this noon-day sun, 1600 candela per sq millimeter. Now convert the Sun's luminance as lumens per sq millimeter. Multiply candela by Pi steradians for 90° practical emitting angle of a diode as offered by the calculator of . The Sun's luminance is 5000 lumens per sq millimeter. Low-glare LED lighting will have diode luminance quite a bit less than 5 lumens per sq millimeter, where any toning down by a lens is with waste of lighting power. Whatever our complaint of LED glare, it is nothing like looking at the Sun. Yet, having brightness down two orders of magnitude from that of the Sun surely is not as good an idea, as being down three orders of magnitude.

Here illustrate Array Luminance with a photo of a Nicor DLS4 luminaire, to be mentioned as especially glaring. It will not be correct or fair, to credit diminished glare to the full size of a lens, where the array is much smaller than the lens. Concentrated luminance of an array is quite visible at lens center.

A luminance table for 4" luminaires, in my opinion, should be for about 500 lumens output, like that of the 4" Glimpse, that I have loved. Please see that glare numbers are especially high for this "family." Brightness is pulled from them out of proportion to their size. Look for more-considerate glare in LED downlights of larger size.

Here are photos of luminaires with lens removed. Clockwise from top left: First Version 6" Glimpse , Nicor DLS10 , Utilitech 0752125 , 4" Glimpse , First Version Sylvania 70732 .
Sylvania 75094, 3000°K, 900 lumens, discontinued at Lowe's in deference to 750 lumens Utilitech 0752125. 

Nicor DLS56, 3000°K, 1022 lumens.

Home Depot / Commercial Electric T67 and T47, 2700°K, 650 lumens and 600 lumens, improvements of 2016 with 5 mm diodes, no longer losing efficiency by recess in luminaire. 

Verbatim 99001, 3000°K, 740 lumens. 

Among 750 lumens LED downlights, initial offerings have been by far, easiest to look at. See that diode luminance of as little as 1.28 lumens/ mm2 was achieved. Convert to lux as times 106, 1.28x10lux. A unity value of diode lumens/ mm2 might be ideal, with luminance at size of the diode array smaller by one order of magnitude.

The evolution of luminance in 1000 lumens luminaires is also in the direction of worsening glare. 

Perhaps, the best way to control glare is with good edge lighting, as achieved with 
Conturrent™ LED Downlights .

The 250 lumens Conturrent has twenty diodes 3.5 mm square. Diode area is 245 sq mm. Diode luminance is one lumen per sq mm, one million lux. The thick acrylic lens is not obscuring. An etched downward face directs the light output at excellent efficacy of 83 lumens per watt.

The readily-available Cooper SLD4 and SLD6 LED Downlights have much greater diode luminance. Array luminance with edge lighting needs definition. Where etched lens area of Conturrent might correspond to an array fully dispersed on the lens, lens area may not similarly soften the glare with the three clusters of three small diodes in SLD4 and SLD6. Moving patches of brightness on SLD4 and SLD6 may correspond to some phenomenon of extreme energy dispersal. 

It is not fair to credit this Cooper SLD6 with even light dispersal to the open diameter of the lens. There is large light concentration at the three diode strips and at random, highly glaring anywhere. Without even dispersal, lens diameter is undefined. I measured 14 watts draw for Cooper SLD6, and 3 watts for Conturrent. 

Add a reference found by Google search luminance per unit of diode area . 
 here with gratitude an entire needed chapter is free.
A III - IV LED, whatever that means, is credited 1,000,000 to 10,000,00 candela per sq meter. About 1.6 candela per sq meter for Nicor DLS10 is at the low end of this range. Too-glaring Nicor DLS4 is within the range. OK Utilitech 0752125 is way beyond this range. The intervening lens modifies what the eye will tolerate. Definitions get murky for needed conditions beyond a lens, and for innovation in the nature of a lens. I believe lens nature is consistent for luminaires mentioned here. The very thick lens of cheap point-source LED bulbs is of strange other nature, losing half of the emitted light to achieve glow of a sphere.

Google bright light impairing short-term vision 
Find Wikipedia, on Flash Blindness :
Flash blindness is visual impairment during and following exposure to a light flash of extremely high intensity.[1] It may last for a few seconds to a few minutes.

For example, in everyday life, the subject of a flash photograph can be temporarily flash blinded. The bright light overwhelms the eye and only gradually fades. A bright spot or spots may be seen for many minutes. This phenomenon is leveraged in non-lethal weapons such as flash grenades and laser dazzlers.

Friday, May 6, 2016

My Up-To-Date Energy Usage Histories

This is an update of my post More Tracking Of Electricity Usage , dated 11/19/2014. Data is from my own home, and is intended first, to show utilities that better feedback to customers can inspire energy conservation. A longest-possible timeline is needed to see and understand usage change. My usage changed dramatically at end of 2011, where I replaced an electric clothes dryer with a natural gas appliance, and continued to reduce electricity usage: with upgrade of all lights to LED downlights, with elimination of CRT computer displays and with move-out of a boarder. It is nice to see confirmation of all of this sudden economy.

The charting of electricity usage including billed amounts adds important information my utility might not wish me to see, that with base charges, my economy is not fully rewarded. The bill will stay above $20 per month, whatever my usage. It is right that I should know this, and that I might then question too-high base charges.

I find no inspiration in the historical usage bar chart contained in my April, 2016 monthly billing.

I said this in my earlier post:
What I really want, and a purpose of this post, is to inspire utility companies to offer better, routine, reports to inspire customers. 
That is still my intent.

My natural gas usage also changed dramatically in 2012:

The big decline is despite new demand for the gas clothes dryer. It is not a result of lifestyle change. I have always been thrifty, leaving the thermostat at 55°F or less except briefly bumping up as easiest way of avoiding condensation in the bathroom while showering.

Whether or not I could be an example to others, my charts with visible and persisting change, are what a utility might wish for its customers. Let all utilities offer longest-term charting to its customers, upon request. Requests might be routine at onset of home upgrades with weatherization. Let there be annual followups, utility-volunteered, for such requests.