Prior to inclusion in GSA’s library of procedures, documents are reviewed by one or more qualified preservation specialists for general consistency with the Secretary of Interior Standards for rehabilitating historic buildings as understood at the time the procedure is added to the library. All specifications require project-specific editing and professional judgement regarding the applicability of a procedure to a particular building, project or location. References to products and suppliers are to serve as a general guideline and do not constitute a federal endorsement or determination that a product or method is the best or most current alternative, remains available, or is compliant with current environmental regulations and safety standards. The library of procedures is intended to serve as a resource, not a substitute, for specification development by a qualified preservation professional.
We’ve reviewed these procedures for general consistency with federal standards for rehabilitating historic buildings and provide them only as a reference. Specifications should only be applied under the guidance of a qualified preservation professional who can assess the applicability of a procedure to a particular building, project or location. References to products and suppliers serve as general guidelines and do not constitute a federal endorsement nor a determination that a product or method is the best alternative or compliant with current environmental regulations and safety standards.
Gayle, Margot, Look, David, and Waite, John. Metals in America’s Historic Buildings: Uses and Preservation Treatments. Washington, DC: National Park Service, .
Zahner, L. William. Architectural Metal Surfaces. New York: Wiley .
Iron is a dark grey metal and is the major constituent of a range of materials including wrought iron, cast iron, carbonized iron (carbon steel) and steel, each of which has its own unique properties. Iron was first used as a material for tools and weapons. Its uses have since grown to include items for domestic use to architectural building components. The presence of iron in a feature may be detected with a magnet.
Wrought iron differs from cast iron and steel in that it contains less carbon. The three metals are ranked as follows in terms of their carbon content:
Wrought iron: Contains the smallest amount of carbon (less than .035%).
Steel: Contains a moderate amount of carbon (between .06% and 2%).
Cast Iron: Contains the largest amount of carbon (between 2% and 4%).
Soft.
Ductile.
Magnetic.
Strong - high elasticity and tensile strength.
Malleable - can be heated and reheated and worked into various shapes.
Becomes stronger the more it is worked.
Suitable for members in tension or compression (whereas cast iron is suitable for members in compression only).
Stage 1: Preparation of puddled iron.
Pig iron was first smelted in blast furnaces and subjected to a reducing condition when it apparently ‘boiled’.
The boiling iron was worked continuously by the iron puddler and more impurities were removed from the iron, making the iron stiffer.
The iron was boiled until virtually no carbon remained, leaving a pasty mass of iron. This was evident when the carbon monoxide would stop bubbling through the iron.
The iron was then formed into balls to be molded.
Stage 2: Iron balls were hammered with a shingling hammer, to expel surplus slag or cinder (shingled).
Shingling was completed in minutes and the finished product was a bloom of approximately 5 inches x 5 inches x 3 feet.
The bloom, still at bright red heat, was then passed through rolling mills, becoming more elongated and thinner in section after each pass, and finished as puddled iron bar.
Stage 3: The bars were reheated and reworked as required to achieve the desired grades.
This stage increased the ductility and tensile strength of the puddled iron.
The more times the metal was reheated and reworked, the stronger were its mechanical properties.
Historical uses during the seventeenth and eighteenth centuries were typically decorative and included:
Fences, gates and railings.
Balconies.
Porches and verandas.
Canopies.
Roof cresting.
Lamps.
Grilles.
Hardware.
Historical uses during the nineteenth century were more structural and included:
Nails.
Iron cramps (i.e. to secure masonry veneer building frames).
Structural members in tension such as tie rods, bulb-tees and I-beams. The standard sections of wrought iron included bar iron, angle irons, T irons, channel iron (half H iron), rolled girder iron (rolled joist iron, beam iron, I iron, or H iron), various special sections (sash bar, beading iron, cross iron, quadrant iron), iron bars, rivet iron, chain iron, horseshoe iron, nail iron, plate iron, coated iron (tin or lead), and corrugated sheet iron (generally galvanized).
Note: By the end of the nineteenth century, the use of wrought iron for structural purposes had been superseded by steel.
Problems may be classified into two broad categories: 1) Natural or inherent problems based on the characteristics of the material and the conditions of the exposure, and 2) Vandalism and human- induced problems.
Although there is some overlap between the two categories, the inherent material deterioration problems generally occur gradually over long periods of time, at predictable rates and require appropriate routine or preventive maintenance to control. Conversely, many human induced problems, (especially vandalism), are random in occurrence; can produce catastrophic results; are difficult to prevent, and require emergency action to mitigate. Some human induced problems, however, are predictable and occur routinely.
Chemical corrosion can attack decorative and structural wrought iron features in several ways:
Uniform Attack: Corrosion attacks the metal surface evenly.
Pitting: Attacks the metal surface in selected areas.
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Selective Attack: When a metal is not homogenous throughout, certain areas may be attacked in preference to others.
Stress corrosion cracking: Attacks areas in a metal which were stressed during metal working and were later exposed to a corrosive environment. Old, hand wrought iron items are more likely to be affected than are machine rolled wrought iron pieces.
Rust: Probably the most common form of chemical corrosion of wrought iron. It occurs when unprotected metal is exposed to oxygen in the atmosphere in the presence of moisture. Moisture can be in the form of normal humidity, rain, dew, condensation, etc. Other gases, such as carbon dioxide, sulfur compounds, soot and fly ash will exacerbate the corrosion of the iron, as will airborne salts.
Galvanic (or Electro-Chemical) Corrosion: Galvanic corrosion occurs when two dissimilar metals are in contact with one another and an electrolyte, such as rainwater, condensation, dew, fog, etc. is present. Such a reaction will cause one or the other of the metals to corrode. In the case of wrought iron, direct contact with copper or zinc, and to a lesser extent galvanized iron or steel, will cause galvanic corrosion.
Mechanical or physical deterioration:
Fatigue: Failure of metal that has been repeatedly stressed beyond its elastic limit.
Wrought iron is generally fatigue resistant because it is so tough. It will deform considerably, within its elastic limit, without failure.
Even if past overloading has caused deformation, wrought iron fixings will usually continue to function.
Defects in the wrought iron itself, or stress points can cause a feature to fracture.
Heat: Usually in the form of fire, will cause wrought iron features to become plastic, distort, and fail.
Distortion: Permanent deformation or failure may occur when a metal is overloaded beyond its yield point because of increased live or dead loads, thermal stresses, or structural modifications altering a stress regime.
Connection failure:
Chemical and mechanical processes can breakdown or reduce the effectiveness of structural metal fixings such as bolts, rivets, and pins.
Stress failure is often a contributor to breakdown situations. Iron water traps are particularly susceptible.
Traveler reimbursement is based on the location of the work activities and not the accommodations, unless lodging is not available at the work activity, then the agency may authorize the rate where lodging is obtained.
Unless otherwise specified, the per diem locality is defined as "all locations within, or entirely surrounded by, the corporate limits of the key city, including independent entities located within those boundaries."
Per diem localities with county definitions shall include"all locations within, or entirely surrounded by, the corporate limits of the key city as well as the boundaries of the listed counties, including independent entities located within the boundaries of the key city and the listed counties (unless otherwise listed separately)."
When a military installation or Government - related facility(whether or not specifically named) is located partially within more than one city or county boundary, the applicable per diem rate for the entire installation or facility is the higher of the rates which apply to the cities and / or counties, even though part(s) of such activities may be located outside the defined per diem locality.
Gates mark the entrance to your castle, your home. They should be beautiful, functional and also elegant, while speaking volumes about the residents. That is exactly what you get with wrought iron gates. Such gates can make your property stand out in the neighborhood with very little effort. Did you know that wrought iron is used extensively in building colonial and Victorian homes?
Here are top 10 reasons why wrought iron gates are a great choice.
1. Superior Rust Resistance
Wrought iron is more resistant to rust than regular iron because it is an alloy. The iron is mixed with a material called slag, which is fibrous in nature, and this makes wrought iron more resilient to rust. So, the beauty of your wrought iron gate is long-lasting.
2. Restoring Wrought Iron Gates is Easy
If you have a wrought iron gate and it looks a bit tired, don’t worry. Just bring out your paint box and give the gate a makeover. If you do a simple paint job, the gate will look great for about 3 to 4 years. A more elaborate paint job will sustain the appearance of the gate for about 10 years.
3. Extremely Durable
Wrought iron is more durable compared to vinyl and wood. It is a tough material and this makes it more impact resistant compared than most other types of material used for making gates. The durability of wrought iron makes it resilient to bending, denting and shock. Wrought iron is very strong and malleable.
4. Boost Security of Your Property
With kids and pets in the house, one of your main concerns is security. The last thing you need is kids making their way onto the road unsupervised or taking a dip in the swimming pool without an adult around. You can install wrought iron gates to your property, fencing as well as swimming pool fencing. The gates form excellent barriers since they are usually high. This keeps kids and pets out of trouble and prevents unwanted guests from gaining access to your property.
5. You can Customize the Design of the Gate
One of the winning qualities of wrought iron is its malleability. This means the alloy is elastic and ductile, and can be shaped into any design you want. The feature of wrought iron allows you to come up with stylish, elegant and unique gate designs, something you can’t do with many other materials.
6. Wrought Iron is Artistry at Its Best
The iron forging process and the manual working with special tools produces an end product that looks stunning and spellbinding. The person who designs wrought iron gates is nothing less than an artist and the way the gates are designed and created are nothing short of art. The superior handiwork that goes into making these gates clearly demonstrates there is a fair bit of artistry involved.
7. Easy to Repair
If your wrought iron gate (or a portion of it) requires repairs, you don’t have to spend money to replace the entire gate. The damaged parts of the gate can easily be repaired by a professional who specializes in wrought iron gates and fencing, and this will restore your gate to its former glory.
8. Adds Value to Your Property
A wrought iron gates adds a certain charm, beauty and appeal other gate materials can’t really offer. As a result, the resale value of your property increases. So, if any time you decide you want to sell your home, the presence of the gate will allow you to ask for a higher selling price compared to other properties in the neighborhood.
9. The Gate Can be a Reflection of Your Personality
Wrought iron can be molded into a range of styles, such as curves, decorative twists and elaborate scrolls. You can even put your initials on the gate – just like we see in mansions and manors. The ability to personalize the gate allows you to make the boundaries of your property your own. You can let your personality shine through the stylish and chic design of your gate.
10. Reduces Your Carbon Footprint
If you are worried about the environment, a wrought iron gate is a great choice. Not only do you save natural resources, since wrought iron gates hardly have to be replaced; you also can recycle the wrought iron. The gate can be sold to a scrap metal dealer and will fetch a handsome price. Alternatively, you can sell the gate to antique stores and architectural salvagers as there seems to be a high demand for wrought iron fences and gates among these professionals.
Know the Downside as Well
While wrought iron gates are gorgeous and stunning and keep your property safe and secure, there are a couple of things to consider before buying:
References:
http://waltham.wickedlocal.com/article//News//?Start=2
http://www.doityourself.com/stry/pros-and-cons-of-owning-a-wrought-iron-fence
http://www.stairsandiego.com/blog/5-benefits-of-installing-wrought-iron-gates/
Want more information on wrought iron components? Feel free to contact us.