Last edited 07 Jun 2017

Lead in construction

Lead sheet roofing.jpg

Contents

[edit] What is lead?

Lead is an element that is naturally occurring throughout the environment. It is a soft, malleable, heavy metal, with a density that exceeds that of most common materials. It has a number of properties that have made it a useful construction material for hundreds of years:

  • High density.
  • Low melting point.
  • Ductility.
  • Resistance to oxidation.
  • Abundance.
  • Ease of extraction.

However, in the late-19th century it was discovered that lead is poisonous, and its use has been less widespread since then. Exposure can result in serious health problems such as kidney disease, anaemia and cancer.

[edit] Construction applications

Lead was used for making water pipes in the Roman Empire, and its production subsequently grew throughout South and East Asia, especially in China and India. Across Europe, lead production began to revive in the 11th and 12th centuries, where it was used for roofing and plumbing. From the 13th century, lead was used to create stained glass. More recently, lead and lead compounds were used for roofs, cornices, tank linings, electrical conduits, cladding, flashing, gutters, and parapets.

Lead was incorporated into soft solder, an alloy of lead and tin, and used for soldering tinplate and copper pipe joints. Lead-based paint inhibits the rusting and corrosion of iron and steel, and continues to be used on steel structures such as bridges, railways, lighthouses, and so on.

Lead roof.JPG

[edit] Health risks

Lead dust, fumes or vapour can be created when lead and items containing lead are processed, worked or recovered from scrap/waste. The body absorbs lead when it is inhaled or swallowed, but generally not through the skin. Lead that is absorbed circulates in the blood and bones where it can be stored for many years without ill health developing.

However, high lead content can cause:

  • Headaches.
  • Tiredness.
  • Constipation.
  • Nausea and stomach pains.
  • Anaemia.
  • Weight loss.

More serious symptoms that can develop over time include:

  • Kidney damage.
  • Nerve and brain damage.
  • Infertility.
  • Cancer.

[edit] Working with lead

Lead can be present in the built environment, particularly in older buildings, in the paint, roofing and pipework.

Work that can produce hazardous lead dust, fume or vapour includes:

  • Blast removal and burning of old lead paint.
  • Stripping of old lead paint.
  • Hot cutting in demolition and dismantling operations.
  • Scrap-processing.
  • Lead roofing.
  • Lead smelting, refining, alloying and casting.
  • Manufacturing leaded glass.
  • Recycling lead-containing materials.

Some prevention and safety techniques that can be employed when working with lead include:

  • Using substitute materials.
  • Leaving lead paint in place if it is in good condition and/or covered by non-leaded paint.
  • Using cold/mechanical cutting instead of hot cutting.
  • Using lower temperatures without blow-lamps or gas torches.
  • Use chemical paint strippers, wet abrasive paper, scrapers and infrared equipment.
  • Wear appropriate respiratory protective equipment, disposable coveralls and gloves.
  • Prevent the spread of dust or fumes with plastic sheeting.
  • Wash and clean surfaces which may have been exposed to dust or fumes.
  • Dispose of contaminated waste safely.
  • Wash hands and forearms thoroughly after working with lead.
  • Avoid hand-mouth/eye contact when in contaminated areas.

[edit] Types of lead

Lead is typically available as as:

  • Rolled lead sheet.
  • Machine cast lead.
  • Sand cast lead.

Rolled lead sheet is available in a range of codes (generally codes 3-8 for construction) as defined in BS EN 12588:2006: Lead and lead alloys. Rolled lead sheet for building purposes. The code relates to the thickness of the sheet; with code 3 being 1.33 mm thick and code 8 being 3.55 mm thick.

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