1. How to build an attractive and efficient main light source for the living room.
2. How to perform the life cycle assessment to quantify its advantages.
3. How to relate those improvements to a person's ecological footprint.
Too often living rooms are dimly lit, or use a central ceiling-mounted fixture that creates an unwelcoming atmosphere. This design provides a remedy by casting a lot of light through an effective diffuser, and can be set on a table for more pleasant effect.
However, the larger ambition of this project is to create a light fixture that minimizes the environmental impact of its manufacture, use, and disposal, so every task is considered with this in mind.
A life cycle assessment is used as a tool to analyze the design decisions.
To conclude the project, I estimate the fixture's ecological footprint.
As you can already see, this will be a wordy instructable.
I promise that you will find something of interest.
Each step tackles a discrete phase of the project, so skip around to see what interests you.
To help you choose, please scan each step's summary and take a look at the pictures.
Step 1: Construction of the base
This step details the construction of the wood base. I use short explanations, drawings, and some photographs. The base material is oak reclaimed from packaging material.
I have attached drawings to supply full dimensional details.
The construction steps are as follows:
1. Prepare two pieces of wood, square across all surfaces:
-the larger piece is 2.5" x 2.75" x 15"
-the smaller piece is 2.125" x 2.375" x 9"
2. Cut the 55 degree slots to get a tight fitting joint.
3. Cut the chamfers on the bottom corners. When cutting the chamfer on the smaller piece, fit it to the larger piece to ensure you do not cut past the point of chamfer intersection.
4. Cut the slots for the the shade mounting pieces.
5. Drill the holes for the light socket assemblies.
6. Drill the hole to house the wire connections.
7. Drill the pilot holes and counter-bores for the screws that will fasten the shade mounting pieces.
8. Rout the slots for the wire runs.
9. Now is a good time to do most of the sanding, as prep for finishing. I found it easier.
10. Glue the pieces together.
11. Clean up the chamfer intersections with a chisel.
12. Drill the wire exit hole.
13. Sand any remaining blemishes.
Step 2: Mounts for diffuser
This step explains the few simple tasks required for preparing the diffuser mounts from flat aluminum stock.
A few fasteners are needed.
The main ingredient is the .125" x 1" flat stock. I found aluminum in 3 and 4 foot lengths at Home Depot.
One great advantage to this material is that no finishing is required! It has a lovely satin surface.
The fasteners required are:
-two round head wood screws to fasten the pieces to the wood base
-four sets of Chicago screws to fasten the diffuser to the mounts; the exact length of these will depend on the diffuser you decide to mount
The aluminum stock must be cut to length: two pieces 11.5" long. A hacksaw is suitable for this.
The cut ends should be cleaned up with a file to remove any burrs and sharp edges.
Each piece needs a few holes drilled:
-one clearance hole for the mounting screw
-two clearance holes for the Chicago screws
Step 3: Finishing the base
The finishing process uses ammonia as a wood dye, and tung oil to seal the wood and add a bit more colour and depth to the grain.
No VOCs or other toxic waste products are emitted.
Following some suggestions from Fine Woodworking Magazine, George Frank's "Adventures in Woodfinishing", and some simple experiments, I found that I was able to get some great effects from using ammonia to stain the oak. Namely, the process accentuated the grain and character of the wood, and gave it a lovely colour.
In a nutshell, it requires exposing the wood to the ammonia vapour. I found that a 24 hour exposure was sufficient to get good results.
You will need a plastic container, with a tightly fitting lid, that is large enough to hold your work.
Pour some ammonia-based household cleaner into the container, enough to barely cover the bottom.
Since the wood should not come in contact with the liquid cleaner, place the work in the container on some form of stand. Keep in mind that the areas that make contact with the stand will not be stained evenly.
Close the lid tightly to prevent the ammonia vapours from escaping, and wait about 24 hours.
There are two significant advantages to using the ammonia vapours:
1. The wood grain is not raised in the process, so no sanding is required afterwards.
2. The vapours penetrated to approximately 1/16" in 24 hours. This bodes well for longevity of the finish. Any scratches and dents, even deep gouges, will not expose lighter wood.
After removing your work from the dyeing container, wait another 24 hours for the absorbed vapours to escape from the wood.
(The leftover cleaning liquid can go back into the original bottle.)
Now it is time to apply the tung oil.
All the books specify using lint-free rags to apply oils; I ignored this advice and regretted it. Do not use cotton flannel.
Take your time to allow the wood to absorb the oil as you apply it (especially to the end grain), then wipe off any major excess before leaving it to dry.
One coat is sufficient to enhance the colour and depth.
If you want the finish to build on the surface of the wood, you will need to apply additional coats of oil. You must wait 24-48 hours before applying a subsequent coat.
Step 4: Diffuser option #1
This option for making the light diffuser uses reclaimed materials, and shows methods of work for mitigating the waste products.
This diffuser uses PVC corrugated roofing.
My neighbour had put three sheets out for the trash, so I scooped them up!
This stuff also comes in colours and different profiles, so don't hesitate to try whatever becomes available.
The first task is cut the diffuser panels to size. A diagram (and PDF file) show the dimensions and mounting hold locations. Cutting with tin snips is easy and clean.
NOTE: my sheets had corrugations spaced 2.875" apart. If yours is different, you may need to adjust the width to get a flat fit to the aluminum mounts.
After some experimentation, I have arrived at a way to effectively diffuse light, and to minimize the creation of PVC dust particles.
Since the product's MSDS sheet doesn't state the dangers of exposure to dust, I have decided that it would be wiser to avoid the dust as much as possible.
To turn the original transparent sheet into an effective diffuser, the surface must be modified.
I used a wire brush mounted in a power-drill to do the bulk of the work of scratching the surface. It is possible to create patterns on the surface, by controlling the direction of the scratches.
PLEASE NOTE: I ran my variable-speed drill at low speed; this created heavier PVC granules instead of fine airborne dust!
The second step in modifying the surface was to wet-sand with 220-grit paper. This adds a necessary layer of diffusion to the surface.
Ideally, you should collect the water and PVC slurry in a tub, let the water evaporate, and send the residue to landfill. Otherwise, the PVC slurry will go through the sewage system and end up in your waterways.
(I mention this because it is in the spirit of minimizing all impacts.)
You are now ready to drill holes along the narrow edges to match the holes in the aluminum mounts.
I suggest practicing on a PVC scrap before performing the task on your finished pieces.
Some plastics will crack and shatter under certain conditions, and drilling holes to avoid this takes a bit of care.
I found that running the drill slowly with a minimum of pressure was gentle, but still effective at cutting the hole.
Be sure to make a little pilot divot, similar to that used for getting accurate holes in the aluminum.
Now its ready to attach.
Step 5: Wiring
Using easily obtained components, the light is safely wired without undue complications.
Compact fluorescent bulbs (CFL) are used to save energy.
The first step in wiring is to get the socket brackets installed in each of the four socket holes in the wood base.
After threading the brackets onto the pieces of threaded rod, I used a nail puller to lock the components together by squeezing the threaded portion into an oval shape. Now, these won't come apart easily.
Place the brackets in the socket holes, through the lock washers, and tighten the nuts on the other end of the threaded rod. The third photo in the series shows a detail of this assembly.
Next comes attaching short lengths of wire to the ceramic sockets. You will need lamp cord in these lengths:
-2 lengths of at least 5.75 inches
-2 lengths of at least 7.75 inches
The lamp cord should have one conductor that is smooth and one that is grooved. The smooth conductor will always be attached to the HOT side of the electrical connections; here it means attaching the smooth wire to the brass screw in the ceramic sockets and the grooved wire to the silver screw.
Now the ceramic sockets are installed by first running the lamp cord through the threaded rod, then fastening the sockets to the brackets in the wood base.
The last length of lamp cord to prepare is for the switch and plug, and can be as long as you like. Mine is about 8 feet long.
Run one end through the wire exit hole in the wood base, split the conductors for a length of about two inches, and tie a knot with one of the conductors. The fifth photo shows how your project should look after this task.
Before you connect the wires, take a moment to observe how all of the wire and connectors will fit into the central hole. If you gave yourself some slack wire to work with, now is the time to trim the wires to get a good fit in the hole.
All of the smooth conductors must be connected together, and all of the grooved conductors must be connected together, using the crimping connectors.
Be sure that you cannot pull apart the connections, then shove the connectors into the central hole.
A good place to put the switch is within 2 feet of the fixture. The inline switch interrupts only one lamp cord conductor; be sure that you use it to interrupt the smooth (HOT) lamp cord conductor.
When attaching the plug, connect the smooth (HOT) conductor to the plug's narrow (HOT) prong. The grooved conductor should be connected to the plug's wide prong.
The last thing to do is to make sure that the connections stay in the hole. I made a simple cover with a piece of scrap steel, and fastened it with two small wood screws. Check out the last photo.
Well? What are you waiting for? Install some light bulbs and test it out!
Step 6: Disposal
While it may seem to soon to consider disposal, since you've only just finished building the fixture, a plan does exist.
The intent of the design is that the fixture's component parts should go into the particular disposal streams that can recover the most value from each component.
To enable this, the fixture is easy to disassemble. There are only a small number of fasteners that attach the diffuser, aluminum mounts, and sockets, to the wood base.
Of course, the first resort would be to re-purpose the components, as this would preserve 100% of their value. The sockets should be reusable, as long as they are not damaged or obsolete. Wire and switch will continue to be useful as long as we use electricity.
Next most likely to be reused are the aluminum mounts and sundry fasteners.
The wood base could be incinerated in a municipal facility or in a home stove or fireplace. This would recover some energy from the wood. The finishing products used on the wood would burn as cleanly as the wood.
The aluminum would best be recycled. It is my belief that in 10 years time, there will be convenient collection for all forms of aluminum and other metals.
The PVC used for the diffuser will probably have to go to landfill.
The crimped wire connectors will go to landfill.
IN-PROCESS WASTE and PACKAGING MATERIALS
I took a photograph of the waste produced through manufacturing, and included the packaging waste from the electrical components.
The wood off-cuts will be used for another project. The chips from planing will go into the garden.
Paperboard packaging materials will be recycled through municipal collection.
The PVC off-cuts will stay in my shop for a while, waiting for suitable project. (In case you haven't already figured it out, I am a pack rat.)
All other materials will go to landfill. This includes: the aluminum chips; the polyethylene bags; the PVC blisters and PVC grinding and sanding dust; and the rag I used to apply the tung oil.
Step 7: The life cycle analysis
This step gives an overview of the life cycle analysis (LCA) process.
It also shows how I used a software tool called ECO-it to performing "screening" LCA studies to compare the environmental impact of my choices for construction materials.
LCA is a method of evaluating the environmental impacts of the production, use, and disposal of products. While I will describe a linear process, in fact it is an iterative process. As information is revealed and the analysis progresses, more questions are raised, and opportunities for product improvement become apparent.
1. Goal definition and scope:
It is critical to develop a clear idea of the goals of your LCA study. This will guide every subsequent step, and keep you focused as you confront all of the questions and information.
I chose to perform an LCA study to help me understand the impact of my decisions, by:
-comparing between incandescent and compact fluorescent bulbs (energy consumption and perhaps packaging waste)
-comparing the relative impacts of production and disposal vs. use
-comparing the use of reclaimed vs. new materials
Determination of the functional unit is influenced by the goal. In my example, the functional unit that I chose was 3600 lumens (light output) for 10,000 hours (this is approximately equal to 3 hours per evening, 95% of the year or 347 days, for 10 years).
2. Constructing a process flow chart:
This task is the first step in what is called the inventory analysis.
The flow chart shows all of the phases in a product's life cycle: from resource extraction, through manufacturing and use, to disposal.
Theoretically, this can involve hundreds of steps for a single product. However, it is most useful if it provides an overview. As the analysis progresses, it will become clearer if particular process steps need to be detailed further.
In ECO-it, I created a bill-of-materials for the fixture. Each component was associated with its relevant manufacturing and use processes, as well as its likely methods of disposal.
3. Collecting the data:
For each process in the flow chart, all inflows and outflows must be quantified. These will describe raw materials, services, energy, in-process or finished products, waste, and emissions.
I measured the amount of each material that I used, estimated the amount of electricity I used with the power tools, and defined the power consumption of the different light bulb types. This data was an input into the project file in ECO-it.
4. Defining the system boundaries:
The boundaries that must be defined are:
-between the product system and the environment: i.e. the points at which materials become inputs and outputs
-between this product system and other systems: i.e. waste management systems
-between relevant and irrelevant processes: i. e. the production of tools
One of the decisions that I made was to exclude the consideration of light bulb production. Firstly, I was unable to get any data on the bulbs; secondly, the fact that 10 incandescent bulbs would be used for every CFL bulb was unlikely to improve the case for incandescent bulbs.
Another boundary decision was how to consider the PVC roofing material saved from landfill.
5. Processing data:
This is tabulation of the data, scaling the inputs and outputs to the functional unit, and grouping like impacts among different processes and materials.
It is also the last step in the inventory analysis.
In ECO-it, this is all done automatically.
6. Classification and characterization:
Different materials and processes create different types of impacts, such as global warming, ecotoxicity, acidification, and nutrification.
This step associates each item in the inventory analysis with these types of impacts.
Again, this creates quantitative data.
To enable comparisons between materials and processes with different impacts (like comparing apples to oranges), these impacts must be given relative weightings.
For example, in comparing the production of energy by coal or nuclear fission, one must value the relative harm created by global warming and that created by radioactive contamination. Otherwise, there is no way to decide which method of production is preferable.
The ECO-it software relies on the Eco-indicator 99 method to weight the various impacts. It boils down each material and process to a single number.
Other methods may be relevant, depending on your purpose.
8. Reporting and improvement assessment:
Reports are created to show the findings, according to your project's purpose.
Opportunities for improvement should be suggested by the reports, probably by first tackling the materials and processes having the largest impacts.
Notes about the LCA data
-All of the data comes from the database supplied with the software. This data is generic; it is based on European industry averages.
-The impact of electricity consumption is also based on the European average, and may be very different from your consumption. This depends completely upon how your electricity is generated: hydro-electric is very clean; coal-fired is very dirty.
"Life Cycle Assessment: What It Is And How To Do It"
-United Nations Environment Programme, 1996
ECO-it (PRe Consultants B.V.)
Step 8: The ecological footprint
Here I make an estimate of the ecological footprint of use of the light fixture, and relate that to a person's share of Earth's productive capacity.
This is where I get into very murky waters.
The basis for calculating an ecological footprint should be straightforward in principle, but the details quickly make it very difficult.
Let's work backwards to explain. The final calculation depends on an estimate of the Earth's yearly productive capacity, usually expressed in hectares.
On the web site for Redefining Progress, they calculate this productive capacity to be 10.8 billion hectares (land and water).
Since the human population numbers 6.6 billion people, each person's share of Earth's productive capacity is 1.6 hectares.
That was the easy part.
By current estimates, Canadians consume the equivalent of 7-8 hectares per person.
How is this possible?
1. The developing world consumes far less. For instance, the average Indian consumes the equivalent of 0.8 hectares.
2. A significant portion of Canadians' consumption is of non-renewable resources (fossil fuels, minerals) which, by definition, cannot be included as part of Earth's productive capacity.
3. The consumption, and volume of waste products output by Canadians' consumption, is actually overloading Earth's productive capacity. Witness the degradation of fresh water resources, depletion of fisheries, and rapid accumulation of greenhouse gases. By the way, Earth's processes for re-absorbing and converting those wastes is included as part of its productive capacity.
So, the ecological footprint of this light fixture can only be calculated by assuming that its manufacture, use, and disposal, consumes renewable resources.
Renewable energies can be used to power the light, which is actually its greatest impact.
The wood would come from sustainable forestry.
The metals must be reused or recycled, and renewable energies consumed to do so.
The PVC comes from our most valuable future resource: landfill. ;-)
Since the use phase so outweighs the production and disposal phases (and that I have no data to use), I have only calculated the footprint of the use phase.
Yearly consumption by the CFL bulbs is 62.4 kWh.
Yearly consumption by the incandescent bulbs is 249.7 kWh.
I used a spreadsheet available from Redefining Progress to calculate the footprint, and have attached it below.
Briefly, 62.4 kWh per year consumes .014 hectares. That equates to 1/115th of each person's 1.6 hectare share of Earth's productive capacity.
In contrast, 249.7 kWh per year consumes .055 hectares. That equates to 1/29th of each person's share of Earth's productive capacity.
(These share figures assume that there is only one person in the household.)
I must confess to being inspired by Bruce Sterling, and his book "Shaping Things", for attempting this project.