Summary and critique of "LEED" 2009 Green Building Design & Construction Reference Guide

Jonathan Ochshorn

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Following is my summary and critique of the Green Building Design & Construction Reference Guide, 2009 Edition. Commentary on the Reference Guide can be found in these red boxes, sometimes within each of the chapter links immediately above, but mostly in my summary and critique of the prior version: Version 2.2 NC.

5. Materials & Resources (MR)

Overview

Sustainable materials:

How to determine costs: either (a) tabulate actual material costs -- basically CSI Masterformat divisions 03-10, plus 31 (foundations) and 32 (paving, site improvements, plantings) -- or (b) take 45% of the total construction costs (which include labor and equipment). Note that Div 12 (furnishings) can be counted if it is counted for all MR credits. Also, if materials are counted for "materials reuse," they cannot be then counted again for either building reuse, construction waste management, recycled content, rapidly renewable matls, or certified wood. (337)

MR contains one prerequisite (Storage and collection of recyclables) and 8 additional credits for NC (not here considering schools and core/shell requirements).

MR Prerequisite 1 Storage and collection of recyclables

Intent: Reduce landfill waste.

Requirements: Collection/storage area provided in building for recycling materials.

1. Benefits/issues.

2. Related credits. ID credit possible by linking recycling to educational outreach (signage and displays).

3. Referenced standards. None

4. Implementation. Avoid conflicts with other program spaces. No specific area requirements, only the following guidelines for commercial building (sf) and recycling area (sf):

building arearecycling area
0-500082
5001-15,000125
15,001 to 50,000175
50,001 to 100,000225
100,001-200,000275
200,000+500


5. Timeline and team. Coordinate with hauler; provide recycling bins; educate occupants and staff.

6. Calculations. None

7. Documentation guidance. Record of plan size and relationship to occupants and staff; special plan showing all recycling storage areas highlighted.

8. Examples. Chart shows typical percentages of the various recyled materials: LEED requires only paper, glass, plastics, cardboard, and metals (59%).

9. Exemplary performance. N/A

10. Regional variations. Big city versus rural areas have different infrastructures; etc.

11. Operations/maintenance. Consider making a policy and education program.

12. Resources.

13. Definitions.

MR Credit 1.1 Building reuse - maintain existing walls, floors, and roof (1-3 points)

Intent: extend life cycle of existing buildings to save resources and culture.

Requirements: Save structural floors, roofs, wall envelope (excluding windows, nonstructural roof material) as follows:

Percentages are based on area, per Table 1 (MR Credit Metrics).

Cannot count as reuse if project has a addition more than twice the total area of the existing building.

1. Benefits/issues.

2. Related credits. Check MR credits 2 and 3; if not enough is being reused to this credit, might work in credit 2 (construction waste management).

3. Referenced standards. None

4. Implementation. Inventory existing conditions, so that surface areas can be determined.

5. Timeline and team. Nothing useful here.

6. Calculations. Do not count surface area of columns/beams. Count only one side of wall/floor-ceiling surfaces. Subtract window areas from exterior walls. Tabulate total existing areas and reused areas so that the percentage reused can be calculated. It is not necessary to count structurally unsound materials, or hazardous materials.

Therefore, if a building structure is 90% unsound and the other 10% is reused, one can get 3 points for reusing (at least 95% of) the 10% that is still useful.

7. Documentation guidance.

8. Examples.

9. Exemplary performance. 1 ID credit for saving at least 95%.

10. Regional variations.

11. Operations/maintenance.

12. Resources.

13. Definitions.

MR Credit 1.2 Building reuse - maintain interior nonstructural elements (1 point)

Intent: same.

Requirements: Reuse interior nonstructural things like partitions, doors, floor and ceiling finishes constituting at least 50% of total surface area of such things, including additions. The credit is non-applicable for additions with greater than twice the area of the existing building.

1. Benefits/issues. same.

2. Related credits. If not enough material is reused for this credit, check MR Credit 2 (construction waste management) or 3 (materials reuse) but not both.

3. Referenced standards. None

4. Implementation.

5. Timeline and team.

6. Calculations

7. Documentation guidance.

8. Examples.

9. Exemplary performance. N/A

10. Regional variations.

11. Operations/maintenance.

12. Resources.

13. Definitions.

MR Credit 2 Construction waste management (1-2 points)

Intent: Reduce landfill and demolition debris; recycle.

Requirements: Make a plan. Recycle or salvage 50% of construction/demolition debris for 1 point (75% for 2 points). Does not include hazardous material or excavated soil/land-clearing debris. Measure either by weight or volume, consistently.

1. Benefits/issues. Reduction in waste has many environmental benefits; "source control" is best strategy. Economics or recycling has improved; in the past, in just didn't pay.

[From Version 2.2 critique] Note that comments within the LEED manual suggest that it would be better to focus on "source control" rather than recycling or reuse; that is, try to generate less waste to begin with by more careful planning or more logical design. Yet this credit rewards the opposite. At the extreme, a project that generates only 1 pound of non-recyclable waste (but no recyclable waste) cannot get this credit, whereas a project recycling half of 100 tons of waste does.

The commentary also points out that low landfill costs in the past made recycling or reuse of construction waste "not economically feasible." This is another contradiction within the LEED approach: it suggests that sustainable design features should be implemented on the basis of profitability, it notices the negative historic results of such an attitude (i.e., the current state of the planet), yet it continues to make the profitable exploitation of the environment the "bottom line" criterion for its recommendations.

2. Related credits. The reused-building portion of a project can actually count as "recycled" waste if it isn't used for MR Credit 1. For hazardous material, see SS Credit 3 (Brownfield Redevelopment).

3. Referenced standards. None

4. Implementation. Lots of record keeping: how much waste is generated; how much of the total is recycled. Note that this seems to punish projects that eliminate waste in the first place: a project that recycles 50% of a huge amount of total waste gets the point, whereas a project that recycles 49% of a tiny amount of waste does not get the point, even though their practice is more environmentally beneficial.

5. Timeline and team.

6. Calculations. Use weight or volume. Include any crushed and reused on-site concrete, asphalt, etc.

7. Documentation guidance.

8. Examples.

9. Exemplary performance. Extra point (Innovation in Design credit) for achieving 95% diversion from landfill.

10. Regional variations.

11. Operations/maintenance.

12. Resources.

13. Definitions.

MR Credit 3 Materials reuse (1-2 points)

Intent: Reuse material rather than buy "virgin" products.

Requirements: If 5% of project material cost is in "salvaged, refurbished or reused materials," take 1 point; if 10%, take an extra point. Note: the unit of measurement here is cost. Do not include mechanical, electrical, plumbing [MEP] components; and only include furniture if it is used in MR credits 3 - 7. Otherwise, exclude furniture.

1. Benefits/issues. Less waste (as old stuff is reused instead of sent to landfills), plus less impact on environment (as less new stuff needs to be made, transported, and so on). Economic benefits either are, or are not, possible, depending on the particular situation.

[From Version 2.2 critique] Note that this calculation is based on cost so that, at the extreme, one could get a point by finding a small quantity of an incredibly expensive object for the building, perhaps a stained glass window salvaged from the Darwin Martin house. Because it might be valued at 5% of the material cost of the building, that single window could generate 1 point.

2. Related credits. Coordinate with MR credit s 1 and 2. Do not count remanufactured materials (although they may count towards MR credits 2, 4). Costs used here lust be consistent with those used in MR credits 4, 5, and 6.

3. Referenced standards. None

4. Implementation. Can use material found on site, as long as it isn't simply doing what it used to do where it used to do it: so a reused door doesn't count (it's already there), but reused door hardware does count (it needed to be re-installed in a new context). Can use material originating off-site, as long as it was used and is now re-used. Material used in this credit cannot be used again in MR credits 1, 2, 4, 6, or 7. Do not include MEP components. Furniture only if used in MR credits 3-7. And furniture taken from the owners old facility only can be counted if more than 2 years old at project initiation.

5. Timeline and team.

6. Calculations. Use cost as measure, either actual materials costs, or 45% of total costs. For on-site salvaged things, use the "replacement cost," excluding labor and shipping. If the actual cost of salvaged material is less than what a new item would cost, use the cost of the new item; that is, use whichever is higher (actual salvaged or equivalent new).

7. Documentation guidance.

8. Examples.

9. Exemplary performance. Extra point (Innovation in Design credit) for achieving 15% salvaged or reused material.

10. Regional variations.

11. Operations/maintenance.

12. Resources.

13. Definitions.

MR Credit 4 Recycled content (1-2 points)

Intent: (a) Improve the market for recycling, and (b) reduce impacts related to the extraction, manufacture, transportation, etc. of new things.

Requirements: If 10% of the material content consists of recycled content (specifically, count all postconsumer recycled content and half of the preconsumer recycled content), take 1 point. If 20%, take an extra point. Note: the unit of measurement is cost, but the determination of the cost of the recycled portion of a product is by weight. Exclude MEP and specialty items (e.g., elevators). Furniture OK, but only if used throughout MR credits 3-7.

1. Benefits/issues. Less use of virgin material; less waste; creation of a market for such products. Note that postconsumer refers to content that is no longer being used for its original purpose; preconsumer refers to content in the manufacturing process that would otherwise be waste. Note that putting "cut" material back into the production process doesn't count as recycling since it isn't a candidate for waste. Postconsumer recycling is considered more valuable "because of its increased environmental benefit over the life cycle of the product."

This could be clarified: if more waste is generated during the manufacturing process than from the actual products themselves, it would seem that preconsumer recycling would be more valuable; therefore, we must assume that postconsumer recycling is considered more important because there is more of it than there is manufacturing waste.

Economic issues are raised that relate to the possibility of increased costs when using recycled materials.

[From Version 2.2 critique] Fly ash is given a bit of a boost in the LEED rating system, by allowing its recycled content within concrete to be based on cement weight, rather than on the much heavier total weight of the concrete. This promotes the use of fly ash because cement is the pricey component of concrete (the heavy aggregate is basically free); since one gets points based on cost, having the fly ash computed as a fraction of the cement weight and cost produces a much higher valuation for the fly ash as a recycled component of concrete. To see why this is so, examine the calculations of fly ash value computed both ways (the numbers are made up so that the calculations are easy to follow, but the basic ramifications of considering only the cement show up clearly):

 

weight

cost

fly ash

1 lb.

$6

other cement

1 lb.

$12

aggregate

8 lb.

$2

The weight of fly ash, measured as a fraction of cement weight = 1/2 = 0.5.
The weight of fly ash, measured as a fraction of concrete weight = 1/10 = 0.1.

The value (cost) of fly ash, prorated according to cement weight and cost = 0.5(18) = $9.
The value (cost) of fly ash, prorated according to concrete weight and cost = 0.1(20) = $2.

In other words, the value of the fly ash is taken as $9, computed per LEED according to its weight as a fraction of the total cement weight; on the other hand, it would be valued at only $2 if computed as a component of the entire concrete, while it's actual cost is $6. Go figure…

Also note that inefficiencies in the manufacturing process are rewarded (since they would tend to generate more pre-consumer recycling material); and bad habits in the production of other goods, for example, over-packaging, are also rewarded, for the same reason.

2. Related credits. Coordinate with MR credits 2, 3; even 5 (Regional materials) and IEQ credit 4.

3. Referenced standards. ISO 14021-1999 (Environmental labels and declarations... where ISO = International Organization for Standardization.

4. Implementation. Put LEED in the specifications: Add LEED general requirements to specification division 01, and specify appropriate products according to these division 01 general requirements.

5. Timeline and team.

6. Calculations. Use cost as measure, either actual materials costs, or 45% of total costs. Count as part of material cost any transportation to site and any taxes; but no labor at the site. Percentage of recycled content in any given product is determined by weight. Exclude MEP [mechanical/electrical/plumbing], appliances, equipment; exclude furniture unless used throughout MR credits 3-7. Default values for steel = 25% postconsumer (but actual value may be much higher, e.g., 90% when using electric arc furnace process). Exception for supplementary cementitious materials (SCMs): base value on weight of cement products only, not of concrete weight.

7. Documentation guidance.

8. Examples.

9. Exemplary performance. Extra point (Innovation in Design credit) for achieving 30% total recycled content value.

10. Regional variations.

11. Operations/maintenance.

12. Resources.

13. Definitions.

MR Credit 5 Regional materials (1-2 points)

Intent: Improve or create market for local materials, reducing transport impacts.

Requirements: If 10% of the material content "has been extracted, harvested or recovered, as well as manufactured, within 500 miles of the project site," take 1 point. If 20%, take an extra point. Exclude MEP and specialty items (e.g., elevators). Furniture OK, but only if used throughout MR credits 3-7.

1. Benefits/issues. Reduces transport. Transport has negative impacts on the environment (pollution) and depletes fossil fuels. LEED also adds another environmental impact which seems indistinguishable from the first: "It also is important to address the source of raw materials used to manufacture building products..." In other words, both the manufacture as well as the mining/harvesting activities must be within 500 miles of the project.

[From Version 2.2 critique] Again the 10% (or 20%) is based on cost so that a single diamond of sufficient value used as decorative embellishment for a building in Lichtenburg, South Africa, would presumably qualify for 2 LEED points, in spite of its dubious relationship to sustainability.

Note that the LEED rationale for using regional materials is not only to reduce the environmental costs of transportation over long distances, but also to support "the use of indigenous resources" for its own sake. The claim that "the local economy is supported..." seems specious, since local manufacturers who sell beyond the 500 mile radius would lose out to the same extent that manufacturers who sell only locally would gain. That "money paid for these materials is retained in the region, supporting the regional economy..." is questionable for the same reason, as well as for other reasons. This is an idealization of a profit-driven, global economic system that knows no national boundaries, let alone artificial boundaries defined by a 500-mile radius. It is also worth noting that, unlike other credits, the value of this credit is not measured by comparing costs of using local/regional materials to the costs of other options. It is also clear that projects that happen to be near manufacturing facilities for products that would have been used in any case get these points "for free."

Also, "support of regional manufacturers and labor forces retains capital in the community, contributing to a more stable tax base and a healthier economy..." (p. 380)

2. Related credits. Coordinate with MR credits 3, 4, and 6.

3. Referenced standards. None.

4. Implementation.

5. Timeline and team.

6. Calculations. Use cost as measure, either actual materials costs, or 45% of total costs. Count as part of material cost any transportation to site and any taxes; but no labor at the site. Exclude MEP, appliances, equipment; exclude furniture unless used throughout MR credits 3-7. Note that salvaged materials, even those used for points under MR credit 3, can be used again here: the point of "manufacture" is taken as the place where the salvaged stuff was taken; while the "manufacturer" location is the home of the vendor. It is also possible to "break apart" assembled products where only parts are regional, basing the cost on the regional fraction measured by relative weight.

7. Documentation guidance.

8. Examples.

9. Exemplary performance. Extra point (Innovation in Design credit) for achieving 30% total regional content value.

10. Regional variations.

11. Operations/maintenance.

12. Resources.

13. Definitions.

MR Credit 6 Rapidly renewable materials (1 point)

Intent: Reduce depletion of nonrenewable and "long-cycle renewable" materials by "replacing them with rapidly renewable materials."

Requirements: If 2.5% of the material content is rapidly renewable, take 1 point. The threshold for such material is a 10-year harvest cycle. It is restricted to plant material, although one would think that the same logic would apply to other material sources (e.g. leather, wool -- see "Implimentation" section below).

1. Benefits/issues. Alleges that rapidly renewable materials "are likely to have fewer environmental impacts" than normal building materials.

This is not explained or proved (e.g., why would logging old-growth lumber have more environmental impacts than logging rapidly-renewable lumber?). LEED mentions "Irresponsible forestry practices" as a rationale for using wheat fiber instead of wood fiber in products (388), but there is nothing inherent in the use of wood fiber that leads to "irresponsible" behavior. This confuses environmental science with the drive to increase profitability. The "economic" rationale is incoherent: land is "saved," faster "payback," although the cost may still be greater than using conventional things.

[From Version 2.2 critique] This credit only makes sense in a context where the destruction of ecosystems is considered a natural outcome of doing business; otherwise, it cannot be rationally explained. The point here is not that one should be surprised that such a relationship exists between competition and profitability, on the one hand, and ecological disasters on the other hand; but only that, once again, the LEED guidelines seem oblivious to the contradiction built into their underlying strategy: specifically, that the drive for profit, responsible for the innumerable negative impacts on the environment underlying the guidelines, is then referenced as both rationale for implementing, and criterion for judging, proposed remediation measures. What this credit points to, without actually requiring it, is scientific ("responsible") management of renewable plant-based materials, whatever their growth cycle might be. Suggesting instead that the use of plants with a short growth cycle should be rewarded makes no sense. Should we also require that the grains we eat every day have a corresponding growth cycle of 1 day? The point would be to organize the production of grain so that its use is consistent with its production cycle. One would expect a similar stipulation for products used in construction.

Note that the LEED commentary suggests that because "rapidly renewable resources may be harvested more quickly, they tend to give a faster payback on investment for manufacturers." First, this makes no sense from an economic standpoint, since "payback" is concerned only with the return on the investment, not the growth cycle of the material (especially since it's not necessary to wait 50 years for a hardwood forest to grow when it already exists); second, what does this have to do with sustainability? The commentary goes on to suggest that such rapidly-renewable resources take up less space since they can be harvested at a more rapid pace, and that this is somehow advantageous: "The land saved [?] from the production requirements of rapidly renewable resources may be used for a variety of other uses..." as if slow-growth forests are not a legitimate use of real estate?

2. Related credits. May be in conflict with MR credits 5 (regional materials). Also, pay attention to IEQ credit 4 to limit VOCs.

3. Referenced standards. None.

4. Implementation. Lists examples of such materials: bamboo (flooring, plywood), cotton (insulation), linoleum, sunflower seed (board panels), wheat (wheatboard cabinets), wool (even though not a plant...), cork, coir and jute (geo-textiles), straw bales.

5. Timeline and team.

.

6. Calculations. Use cost as measure, either actual materials costs, or 45% of total costs. Count as part of material cost any transportation to site and any taxes; but no labor at the site. Exclude MEP, appliances, equipment; exclude furniture unless used throughout MR credits 3-7. It is also possible to "break apart" assembled products where only parts are rapidly-renewable, basing the cost on the rapidly-renewable fraction measured by relative weight.

7. Documentation guidance.

8. Examples.

9. Exemplary performance. Extra point (Innovation in Design credit) for achieving 5% total rapidly-renewable content value.

10. Regional variations.

11. Operations/maintenance.

12. Resources.

13. Definitions.

MR Credit 7 Certified wood (1 point)

Intent: Encourage "environmentally responsible forest management."

Requirements: If half of the cost of wood-based things are certified (per Forest Stewardship Council), take 1 point. Only count furniture if counted in MR credits 3-7.

1. Benefits/issues. Responsible forest management includes sustainable harvesting as well as "preserving wildlife habitat and biodiversity, maintaining soil and water quality, minimizing the use of harmful chemicals, and conserving forests of high conservation value." Economics: the stuff may cost more.

2. Related credits. Any regional forests that qualify (MR credit 5)? Check that the products are urea-formaldehyde free (IEQ credit 4.4).

3. Referenced standards. Forest Stewardship Council web site: http://www.fscus.org. Concept of "chain-of-custody" explained here: companies selling products must complete an audit to justify their FSC certification.

4. Implementation. Pre-purchase by owner may be a good idea; use lower-grades of wood (more readily available).

5. Timeline and team.

6. Calculations.Only new wood products are counted. Compare cost of FSC certified to total cost of new wood. For wood with a partial FSC-certified content (e.g., 50%), base cost on that percentage. Do not count recycled content, even if FSC-certified. This is for new only. Where wood is mixed in a product with non-wood things, determine the cost of the wood based on the fraction of weight it constitutes within the product.

7. Documentation guidance.

8. Examples.

9. Exemplary performance. Extra point (Innovation in Design credit) for achieving 95% certified wood content.

10. Regional variations.

11. Operations/maintenance.

12. Resources. See http://www.fscus.org/green_building

13. Definitions.

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