Your Place: Copper, zinc strips can avert algae stains on roof

Question: Last year, you wrote about what to do about black marks on roofs. You said it was algae that built up from the product used in the shingles, and you gave a remedy for cleaning it off the shingles.

Well, I cut your article out for a spring project and, yep, you guessed it, now that spring is here, I cannot find the article. I wonder if you can tell me again how I can remove the unsightly black marks from my roof easily.

Answer: Fiberglass asphalt shingles these days have a limestone filler instead of the traditional rag filler, and the limestone promotes the growth of algae that shows up in horrible streaks on roof areas that don't get much sun. Have your roofer nail copper or zinc strips on the peaks above these areas, so rain running over the strips will kill the algae. Or look into shingles containing copper to solve that problem.

Whatever you do, don't try cleaning the black stains, or mildew, for that matter, with water and bleach. It will reduce the life of asphalt shingles.

Q: The dinosaur in my basement, which so far has heated my house without major problems, is due for replacement.

My dilemma is: oil or gas?

My small, three-story rowhouse is heated by oil. I have no complaints with the companies that provide the fuel oil and the annual clean-out and service contract.

I suppose the thing that gives me pause about staying with oil heat is the crazy spiking of prices over the last year.

The estimates I've gotten so far for installation of an oil vs. a gas system have been about a wash. So for the long haul, which type of system is likely to be most predictable, operating costwise? (Or am I delusional to think either system will ever again be predictable?)

I'd like to hear the opinion of someone who has nothing to gain from my decision: oil or gas?

A: I've had both oil heat and gas heat, and prefer gas because it seems to be cleaner and more efficient than fuel oil. I suppose my view is colored a bit by the memories of my late-October cleaning of my monster in the basement several years back. On the other hand, I do have a gas condensing furnace - check the Internet for manufacturers' explanations. I've had only two problems with it in the last nine years, and both were the result of improper installation by the original contractor 10 years ago and a previous owner. Frankly, the cost of those repairs was well worth it, considering that I ended up with a reliable servicer.

I don't know anyone who has ever succeeded playing the gas vs. oil price game. I think the key to your decision is the efficiency of the furnace you buy and the warranty and service provided by the installer and the manufacturer, and not trying to second-guess OPEC.

Q: We live on the ground floor of our house and use the upstairs bedrooms and bath only when we have overnight guests a few times a year. Does it make sense to close off those rooms when they aren't in use? If so, should I seal off the return vents as well as the supply vents?

Also, in a recent column you mentioned that adding insulation might be a cause of moisture problems. I'm considering upgrading my attic insulation from R-30 to R-49 by having insulation blown in. Is there any way to determine in advance if this might cause moisture problems? Are there particular steps I can take in advance to avert moisture problems?

A: I'd close the supply vents for sure, but I'm not all that sure about the returns. You might want to give the furnace servicer provider a call to determine whether doing so will affect the efficiency of the unit.

As far as moisture and upgraded insulation are concerned, I'd just keep an eye on things. If you have bathrooms, the dryer, the cooktop, and other sources of indoor moisture properly vented, you shouldn't have a problem.

How do you determine if you have moisture problems in your attic? Moisture will manifest itself as darkened stains on wood surfaces, typically starting at the joints. Damage to insulation is often difficult to identify without feeling the material for moisture. You should also look for mildew or mold that can accumulate on some insulation materials and attic wood and wallboard surfaces.

http://www.philly.com/inquirer/home_design/20090424_Your_Place__Copper__zinc_strips_can_avert_algae_stains_on_roof.html

Rolling mill zinc oxide dusts recycled

Using an innovative procedure, zinc oxide is recycled from steel works dust produced by rolling mills, with GE Fanuc's CIMPLICITY software used to monitor the recycling process. P

Using an innovative procedure, zinc oxide is recycled from steel works dust produced by rolling mills, with GE Fanuc's CIMPLICITY software used to monitor the recycling process, says Chris Milburn, PLC Sales Manager, GE Fanuc Automation (UK) .

The company B U S is one of the leading European suppliers in the field of reprocessing and recycling recoverable materials from industrial processes.

In Freiberg, Saxony, B U S runs an oxide leaching plant.

Since November 2000, a new SDHL procedure is being used to recycle zinc oxide from steel works dust produced in rolling mills.

This procedure was awarded the innovation prize of the Free State of Saxony.

Up to 100,000 tons of steel works dust can be recycled each year.

The new procedure reduces the energy requirement to recover metals such as iron, zinc and lead by more than 40%, while at the same time increasing the plant's throughput by 30%.

The new SDHL procedure is very sophisticated, requiring the highest precision in process parameters.

First, the dust is heated to 1,100 degC in a furnace.

During this step, the zinc is dispersed as powder.

This powder still contains chlorine which needs to be washed out in subsequent stages of the process.

Then, common salt and zinc oxide is obtained by adding soda.

Finally, the zinc oxide is removed from the solution using filter presses and can then be reused for the metallurgical process in the rolling mill.

In order to work properly, this recycling procedure requires a very accurate control of temperature, mixing proportion, flow rate and water conductivity.

The conception, planning, installation and commissioning of the entire control technology was the responsibility of system integrator 'K + L Elektrotechnik' who took six months to realise the project.

The control concept includes a PLC with decentralised peripherals, approximately 300 digital and 50 analog I/Os, Profibus DP-Asi transducers as well as a Display Station 2020 industrial PC running GE Fanuc's monitoring and control software CIMPLICITY HMI Plant Edition.

Communication is carried out via Profibus-DP as well as via an Asi bus between peripherals.

Using the Asi bus enabled a reduction in control costs of 25%.

Altogether, the CIMPLICITY HMI monitoring and control software processes data from around 700 data points.

The software is installed on an industrial PC running under Windows NT.

The CIMPLICITY HMI software monitors the temperature, filling level, flow rate, density and conductivity parameters.

When the monitoring and control software had to be selected, the following features were considered to be CIMPLICITY's strong points: * The workbench and the 'drag and drop' functionality enable a quick configuration of the application.

* Integration with third-party controllers is very easy.

I/Os are accessed directly, there is no need to develop separate modules or I/O connections to access the PLC memory.

* The system is very easy to operate.

When asked about his experience with CIMPLICITY, Jan Kermer, Managing Director at K+ L, replied, "As system integrators, we appreciate the easy configuration of the CIMPLICITY software.

Also, with over 100 drivers, integration of third-party products into a control concept is no problem at all." The plant was put into service over a year ago and has been running smoothly since then.

B U S is now thinking about installing a second furnace in the plant which, of course, would also be monitored by CIMPLICITY HMI.

GE Fanuc Automation is a leading global supplier of automation controls.

These products and services include a wide range of CNCs, motion control products, micro to high-end PLCs, monitoring and control software products, and CO2 and YAG lasers.

GE Fanuc Automation is a joint venture between GE and FANUC and the company's European headquarters are at GE Fanuc Automation Europe in Luxembourg.

http://www.manufacturingtalk.com/news/geu/geu128.html

Reduced China buys sink zinc exports

Weaker buying by Chinese importers and the reduced availability of recovered zinc from electric furnace steelmakers trimmed U.S. exports of the galvanizing metal by nearly 24 percent in January.

Exports of the galvanizing scrap metal slumped to 1,985 short tons from 2,610 tons in December and less than half the 4,026 tons sent overseas in January last year, according to the latest figures from the...

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Reduced+China+buys+sink+zinc+exports

Zinc 'Grand Designs' honours for sustainability

Though less well known for standing seam systems than aluminium, zinc is now receiving widespread public attention as a consequence of projects featured in, for example, the 2007 Grand Designs Awards.

Growth in specification of zinc as a building product in the UK owes much to its lasting appearance, malleability and corrosion resistance.

It blends well with wood, stone and concrete and provides a contrast with the plethora of glazing finishes available.

As a roof covering it can be formed into the most complex shapes and used at pitches as low as 3deg.

Though less well known for standing seam systems than aluminium, zinc is now receiving widespread public attention as a consequence of projects featured in, for example, the 2007 Grand Designs Awards.

Bere Architects' 'Focus House' in the Finsbury Park area won 'Best Eco House', having used VM Zinc Plus in a Quartz-zinc finish with a concealed zinc rainwater system.

The system uses a patented pre-weathering process to produce a patinated appearance and texture which resembles aged material.

The finish requires no surface treatment or painting and is resistant to surface marking during installation.

Osborne Homes' Demonstration House built recently at the BRE, was designed as an entry in the 'GBP60K house' competition to demonstrate low cost, affordable, sustainable construction incorporating the latest thinking in waste reduction and energy efficiency.

Zinc was used for roofing, guttering and cladding in a structure that was built in a day and a half.

By complete contrast, for his design of Quarry House in Sevenoaks, Architect Steve Marshall of Munkenbeck and Marshall specified a combination of larch for the structural timber and zinc for the dramatic curved roof.

The silver grey larch will blend with the zinc's gradual, natural patination.

Like the timber, specified from an FSC accredited source, the zinc was chosen for its sustainability.

30% of all zinc manufactured now uses recycled material while in Western Europe, 90% of rolled zinc recovered from roofs and rainwater systems (around 100,000 tonnes each year) is now reclaimed.

There is already evidence of the knock-on effect in the UK; for the restoration of Brighton railway station the original zinc supplied by VM Zinc a century ago was removed, recycled and new material from the same manufacturer applied.

Recycling may owe much to the trend towards care of natural resources, but a high residual value of 60% to 75% of the current new material cost is, undeniably, drawing attention to its viability.

Energy used to manufacture, whether from ore or reclaimed material, is the lowest of the non-ferrous metals - less than half that of copper, and a quarter that of aluminium.

Even against the cost of manufacturing using recycled aluminium, zinc's energy consumption is around a third lower.

New technology affecting zinc manufacture now enables production of materials in a variety of finishes and colours.

In addition to Quartz-zinc, Anthra-zinc, a deeper charcoal colour, is produced for more contemporary architectural styling, while the newly launched Pigmento range offers the naturally grained texture of pre-weathered Quartz-zinc in blue, red and green.

Zinc's use in urban environments began to increase once risk of smog and acid rain-induced sulphur dioxide corrosion was eliminated following fossil fuel eradication.

This now means that the product's quoted design life invariably exceeds 50 years.

As an alternative to cast iron it is also significantly lighter and less expensive - a 2-metre length of 125mm wide half-round zinc gutter weighs only 2.75 kg compared to cast iron at over 8kg.

Although still relatively new as a guttering material in the UK, zinc is beginning to fill a void between inexpensive but visually uninspiring PVCu and more traditional but expensive cast iron.

Even in coastal environments, corrosion resistance is higher than that of aluminium and, unlike cast iron, it is not susceptible to impact cracking.

At 150N/mm2, tensile strength is high too, and resistance to surface spread of flame is to Class 0 / Class 1.

As an environmentally safe option to lead, zinc is now finding increasing use as an alternative to lead on heritage projects.

A 62-section cupola zinc roof and central finial, specified by Dannatt Johnson for the recently refurbished mid-19th century Clapham bandstand is a good example of a roof involving intricate detail.

Thought to be the biggest bandstand of its type remaining in the UK, it provides a vivid contrast to contemporary designs with standing seam roofs such as the Coptic Orthodox Church in Stevenage.

Maintaining an ecological equilibrium is essential for any naturally occurring material.

Analysis of zinc concentrations in the Rhine, however, confirms that the balance is still well within acceptance tolerances.

Emissions resulting from zinc manufacturing continue to reduce (down 43% between 1983 and 1995), while the diversity of uses for reclaimed product, which include galvanizing, zinc oxide and brass production, suggests that natural extraction will remain within manageable proportions.

With zinc use in the UK likely to be stimulated by the growing market for reclaimed and natural building materials, its future looks healthy in every respect.
http://www.buildingtalk.com/news/umi/umi105.html