End User Focus: On a roll: glass fibre

By Siobhan Lismore-Scott
Published: Monday, 01 October 2012

While the dip in construction has hit sales of glass fibre, the move towards increasing energy efficiency has maintained strong global demand.

The fastest growing industry sector for glass fibre is in insulation, as populations become more concerned with energy conservation. The European Union’s push to improve energy consumption by 20% by 2020 has seen many governments offer free or subsidised insulation this is welcome news for glass fibre minerals such as kaolin and borates (see panel).


Outside of the EU, Russia is aiming to reduce energy consumption by 40% in 2020 and China has invested heavily in rebuilding ‘energy poor’ housing and has pledged $23bn for energy efficient projects.

In the US, the Obama administration has launched ambitious energy saving initiatives, including a $2,000 tax credit for residential homeowners who insulate properly and make their existing properties more energy efficient.

In Australia, the government pledged in 2009 to install free ceiling insulation in around 2.7m homes under the Energy Efficient Homes Package. However, the Home Insulation Programme was later shelved in favour of a new scheme and then abandoned in April 2010. The scheme is remembered as being controversial, due to workers deaths while installing the insulation, and costly, due to compensation payments.

However there is no doubt that the push from governments has driven up demand for glass fibre as households take advantage of insulation schemes.

“The tighter energy efficiency standards introduced in many countries are helping to drive up demand for core thermal and acoustic insulation solutions,” Saint-Gobain said in its 2011 annual results.

The energy efficiency drive has also led to new sources of energy being developed, which has offered opportunities for glass fibre applications.

Wind turbine blades, a relatively new growth area, are made from glass fibre, but increasingly, also from carbon fibre.

The cost-effectiveness of using carbon over glass fibre for wind turbine blades increases with blade size, and in one example of a 57-metre blade, use of carbon led to a 27% weight reduction alongside a 14% cost increase compared to glass-fibre-only designs: at 90 metres length the cost comparisons are predicted to be about the same.

Other aspects, such as labour and load on other turbine components, can also contribute to the cost-effectiveness of carbon fibre usage.

For example, a very labour intensive stage in blade manufacture is the hand laydown of the glass fibre and the difficulties of automating this are that the fabric is limp and difficult to handle.

Ohio-based Owens Corning Corp is the world’s largest producer of glass fibre. The company was initially founded as Corning Glass. In 1935 Corning Glass approached Owens Illiniois with a proposal to join forces and the new company was founded in 1938. Today it operates in 28 countries.

Johns Manville (JM), based in the U.S. and founded in 1858, holds the second leadership position in the industry.

JM manufacturing facilities are in North America, Europe and Asia. Founded in 1858, JM has four main business groups: Engineered Products North America, Engineered Products Europe/Asia, Insulation Systems and Roofing Systems. Revenue, on average, is around $2.5bn pa.

Both Owens Corning and JM experienced bankruptcy because both used asbestos, as well as glass fibre, as an insulator.

In Europe, and in the US, Saint-Gobain, of France, is also an important player. The company operates under its US subsidiary, Certain Teed Corp., in the US, and as Isover in other parts of the world. Isover also manufactures mineral wool. It posted sales of €376.7m ($492.5m*)in 2011, but this is across the Isover group.

Knauf Insulation is active in more than 35 countries with 30 manufacturing plants. The company, which is part of the German family-owned Knauf Group, had a turnover in excess of €1bn ($1.3bn) in 2010.

It is the leading UK supplier of glass fibre. It was formed in 1946 as Fibreglass Insulation and has been previously known as Pilkington Insulation and Owens Corning. This was before the involvement of Knauf, with KnaufAlcopor.

In Asia, Jushi Group, based in China, claims to be the market leader. It feeds the domestic market as well as exporting to North America, the Middle East, Europe, Southeast Asia and Africa, it says, with the export volume accounting for 50% of its total sales volume.


Like most industrial mineral endmarkets, glass fibre has also seen a slowdown in demand due to falling construction rates.

The glass industry was among the sectors which suffered from the beginning of the financial downturn. Mainly depending on the construction, automotive and consumer goods markets, it was affected as early as Q4 2008, all segments included.

In 2009 a report, Glass Fibers, from The Freedonia Group Inc., Cleveland, US, marked demand by 2013 to expand by 3.3% pa, to 7,200m lb.

The report outlined that the glass fibre industry will be driven by efforts to lower production costs and broaden markets.

Best growth prospects are anticipated for glass wool fibre, with textile glass fibre demand constrained by maturing markets and competition from imported fibres.

But in its most recent financial results, Owens Corning said that demand had not been as high as anticipated.

“Our second-quarter financial performance represents progress over the first quarter, but the rate of improvement is below our expectations, and we no longer see 2012 as a year of adjusted EBIT growth,” CEO Mike Thaman said at the beginning of August.

“Historically, the long-term global growth rate for glass reinforcements has been 5% to 7% per year, growing with industrial production. We believe that the slower-than-anticipated growth in the market in 2011, particularly in the second-half, has contributed to Owens Corning and our competitors holding excess inventory at year-end. This has placed pressure on pricing, particularly in Europe and Asia, with overall declines in the low-single digits, although the impact has been somewhat less than we’ve seen in the past,” Duncan Palmer, CFO, outlined in a webcast to investors.

The company revised its earnings expectations due to weakness in its roofing products.

“Based on the current market outlook for industrial production growth and continued progress with these actions, the company expects composites financial performance to improve in the second half of 2012, positioning the business to return to double-digit margins in 2013,” it said, showing that there is some expectation for growth by 2013 - although this may not be as fast as expected.

JM meanwhile said that it expects the glass fibre market to continue growing at two times the GDP rate.

“In general, we expect the fibre glass market to continue its growth rate at two times the gross domestic product, driven by organic growth and material substitution - largely metal,” Enno Henze, vice president and general manager of Johns Manville’s Engineered Products Europe/Asia business, told IM. “ There is a lot of focus in the transportation sector to seek lightweight solutions to drive fuel efficiency in cars and trucks.”

Wind turbine blades are an exciting growth
market for the glass fibre industry.

Looking ahead

Mineral substitution

JM told IM that it has seen some mineral substitution in the glass fibre market.

“As the glass fibre industry is under strong price pressure, efforts to optimise the glass composition are increasing,” the company said.

“There is an ongoing effort to use lower-cost sources, keeping the same glass formulations but using different minerals. This incorporates productivity considerations to achieve higher throughput; for instance, through the use of quicklime,” the company added.

Borates, a mineral commonly used in glass markets, have seen prices increase over the last 12 months on the back of tightened supply. Prices for borate grades quoted in IM have increased by almost a third in the last 12 months in some cases (see p68-71).


There are some reports which suggest that glass fibre also comes with its own health issues, but this has been refuted by the North American Insulation Manufacturers Association (NAIMA).

Although both glass fibre and asbestos are made from silica filaments, NAIMA claims that asbestos is more dangerous because of its crystalline structure, which causes it to cleave into smaller, more dangerous pieces and remain in the body.


Anti-dumping is another issue in the glass fibre industry as China’s hold on the industry threatens to intensify.

India and Turkey have already imposed anti-dumping measures on glass fibre from China. In India the provisional measures are at 40.86% and in Turkey 38%.

In the EU, antidumping duties of 43.6% came into effect for glass fibre in 2010, for a provisional period.

The European Glass Fibre Producers Association (APFE) welcomed the antidumping duties, introduced in 2011 in the EU. The association stated that since 2004 the market share held by Chinese producers in Europe has seen a massive increase and the European industry has suffered from significant price undercutting, seriously damaging profitability, the ability to invest and employment in the sector.

In the UK, antidumping duties were extended to Malaysia, Thailand and Taiwan in July 2012, to stop Chinese- sourced material finding its way to the UK market.


REACH (Regulation on Registration, Evaluation, Authorisation and Restriction of Chemicals) is also an issue as certain borates have been classified as Substances of Very High Concern (SVHC). So far, this classification only refers to borate grades mainly used in detergents, however.

Growing stronger

The strength of fiberglass has also been researched, with results that suggest it may be a lot more durable than previously thought.

In the February 2012 issue of the Journal of Non-Crystalline Solids, Dr Prabhat K Gupta and his co-authors describe an improved method for measuring the strength of e glass and other glass fibre, including those used in fiber-optic communications.

To measure the ideal strength of e glass, experiments were undertaken on glass fibre that was 100 micrometers thick - about the same thickness as a human hair - held at -320 F (-195 C). They bent single fibers into a “U” shape and pressed them between two metal plates until the fibers snapped at the fold.

The fibers withstood a pressure of almost 1.5m lbs per inch, roughly 1.7 times higher than previous recorded measurements of 870,000 lbs per square inch.

Cracking under pressure?

“The weak areas are still in infrastructure and building materials, where consumption has slowed down due to reduced public spending (partly driven by the termination of stimulus packages/measures),” JM told IM.

The drive towards energy efficiency will be the main source of demand for glass fibre as populations insulate their homes and wind turbines continue to be manufactured as the world looks to renewable energy.

As construction markets suffer on the back of a depressed economy, glass fibre still looks strong because of the push towards greener energy.

* Currency conversion calculated on 18 September 2012

Back to basics

Glass fibre is made up of bulk, chopped fibres or strands of glass and durable plastic resin. It is used in reinforcing plastics and composites as well as other specialised electrical and thermal applications.

Minerals used in the creation of glass fibre are silica sand, limestone, soda ash, borates, kaolin, lithium minerals, potash, feldspar, fluorspar, and sodium sulphate.

Glass fibre is called by several different names: glass fibre, fibre glass, glass wool, glass reinforced plastic, GRP, glass fibre reinforced plastic, GFRP.

The most common glass fibre is a calcium-alumina borosilicate with an alkali content of less than 1%. It is commonly known as e type glass, since it was originally developed for use in electrical insulation systems.


Glass fibres are produced by running molten glass from a direct melt furnace into a platinum alloy bushing containing a large number of small holes, from each of which a glass filament is drawn.

Filaments for commercial use are normally between nine and 15 microns in diameter (see table). The filaments are layered with an emulsion before being gathered into fibres.

The fibres are strong and they have excellent electrical properties. They are also resistant to most chemicals and moisture wear. They are non-combustible with a melting point around 1500 C.

The resins most commonly used in the manufacturing of glass fibre are unsaturated polyesters dissolved in styrene. The polyesters are produced by reacting various organic acids (usually phthalic or maleic anhydrides) with an alcohol such as propylene glycol or ethylene glycol, East Coast Glass fibre Supplies explains.

Depending on the particular alcohol or acid used, various types of resin can be produced, meaning that it is possible to have polyesters tailor-made for the intended end market.

The solution sets to a hard substance, a co-polymer of polyester and styrene, by the cross linking of molecules (polymerisation). This hardening process is commonly referred to as ‘curing’.

“Partial cross-linking occurs spontaneously, thereby limiting the storage life of the resins, but, for the process to take place quickly and completely it has to be activated by two additives. One is a catalyst, which triggers the process and the other is an accelerator, which - as the name implies - speeds it up,” East Coast Glass fibre Supplies explains.

Internal heat generated within the resin during curing can reach temperatures of 170 C. The curing of polyester resins takes place at room temperature.

Fiberglass cloth is differentiated into two separate grades: e glass is a lower grade, while s glass is used for applications that require greater strength.

E glass was created in the 1950s to insulate electronics. Today, uses for glass fibre include mats, thermal insulation, electrical insulation, sound insulation, reinforcement of various materials, tent poles, sound absorption, heat- and corrosion-resistant fabrics, and automobile bodies.

Glass fibre is used in consumer goods like hot tubs, bath tubs and boats. It is also used in water storage tanks, for pipes in the oil and gas industry, as well as in households and offices, in roofing and cladding.