Sunscreen and UV Clothing : UPF and SPF Explained
Some useful information on SPF Sunscreens and UPF Sun Protection Clothing from sun-togs.
SPF (Sun Protection Factor) & Sunscreens
SPF is a measurement specifically for sunscreens. It is an indexed number based on the amount of UV radiation necessary to turn skin treated with sunscreen red compared to untreated skin. The protection a given SPF provides will vary depending on your skin type. For example, SPF 10 allows you to stay in the sun for ten times longer without burning than you could without sunscreen applied. If you are fair-skinned person and normally at risk of burning in ten minutes under the noon day sun, SPF 10 sunscreen would enable you to remain in the sun for 100 minutes before you are at risk from sunburn. If you have a darker skin less prone to burning and say burn in 20 minutes without sunscreen you could stay out in the sun for 200 minutes before burning. Therefore your choice of sunscreen protection should be governed by your skin type and the amount of time you are expecting to spend in the sun.
Good protection depends upon correct use of sunscreen. General advice is that you should apply it 20 minutes before going outside, remembering to re-apply frequently because activities such as wiping your face or playing in the sand can rub it off. Recent research has shown that children often get their worst sunburn of the season while wearing high SPF sunscreen. The reason seems to be complacency: they thought they were protected but forgot to reapply...
The SPF index refers only to UVB protection. Therefore, be wary of "broad spectrum" (protection from UVA & UVB radiation) claims on sunscreens. While many sunscreens actually do protect against UVA rays, there are a few which do not.
Although there is no agreed upon international standard for UVA protection. in the UK we do have an Industry recognised standard which is the UVA star rating system. Most leading brands subscribe to this system under license from Boots The Chemist Ltd, when selling their products in the UK.
The ‘star system’ is used to indicate UVA protection. This is composed of a scale with ratings from zero to five stars (see table). The higher the number of stars, the greater the protection against UVA. But the star system only measures UVA protection in relation to UVB, so it can be confusing. A sunscreen with a higher SPF factor and 3 stars may give more UVA protection overall than a lower value SPF sunscreen with 4 stars.
This system includes a scientific test protocol that measures the ratio of UVA/UVB absorbance for the sunscreen product. This is then used to allocate the appropriate UVA star rating category.
There are no laws requiring manufacturers to test sunscreen. But there are laws about what they can say about them. If they specify a given SPF rating for their sunscreen, it must have been tested, because the manufacturer has to be able to produce the evidence supporting its claim. If a company were to claim that their product had been tested when it hadn’t, they risk prosecution. The law on sunscreen comes under the European Community Cosmetics Directive. This legislation regulates all aspects of the manufacture and sale of cosmetics, including sunscreen. It is adapted into UK law as the UK Cosmetic Products (Safety) Regulation of 1996. One of the requirements of this legislation is that claims made about cosmetic products are supported by scientific evidence. The European Commission is reviewing the requirements for information on sunscreen. They want to make the information easier for people to understand. And they are also recommending an internationally agreed measure of UVA protection.
Sunscreens are also covered by legislation that protects consumer rights. The General Product Safety Regulation (1994), the Trade Descriptions Act (1968) and the Sale of Goods Act (1979) all require that products sold to customers are safe and do what they say they do. All major European manufacturers of sunscreens have entered into a voluntary agreement via The European Toiletry and Perfume Association (COLIPA). As a result, the COLIPA SPF Test Method is widely used, although companies are not legally required to use this particular test.
The COLIPA SPF test method recommends that at least 10 healthy volunteers are used in the testing. The volunteers must be pre-screened to find out how long it takes each of them to burn. The same amount of sunscreen should be applied to each volunteer so that the results are reliable. 2mg of sun cream has to be used on every square centimetre of skin. This is certainly far more than most people would normally apply. The test is restricted to the area of the back between the waist and shoulders.
Types of sunscreen
Dermatologists generally recommend use of a broad spectrum sunscreen (broad spectrum sunscreens protect against UVA & UVB) with a min SPF of 15 to SPF 30.
Active ingredients of sunscreen will vary depending on the brand but can be divided basically into chemical or physical agents or a combination of both. Chemical sunscreens work by absorbing the energy of UV radiation before it affects your skin. Physical sunscreens actually block/reflect or scatter UV radiation before it reaches your skin. Some sunscreens combine both chemical and physical agents.
Types of physical sunscreens that are generally available are zinc oxide and titanium dioxide. Both provide broad spectrum UVA and UVB protection and are gentle enough for everyday use. Because these are physical blocking agents and not chemicals, they are especially useful for individuals with sensitive skin, as they rarely cause skin irritation.
Most chemical sunscreens are composed of several active ingredients. This is because no single chemical ingredient blocks the entire UV spectrum (unlike physical sunscreens). Instead, most chemicals only block a narrow region of the UV spectrum. Therefore, by combining several chemicals, with each one blocking a different region of UV light, one can produce a sunscreen that provides broad spectrum protection. The majority of chemical agents used in sunscreen work in the UVB region. Only a few chemicals block the UVA region. Since UVA can also cause long-term skin injury, many dermatologists recommends sunscreens that contain either a physical blocking agent (e.g. titanium dioxide or zinc oxide) or Avobenzone (also known as Parsol 1789).
A Note on Organic Sunscreens;
When it comes to sunscreens, the term “organic” does not have the same meaning that it does when used in relation to food. It does not mean that a sunscreen is “natural” or contains fewer chemicals.
“Organic” is a technical term used in chemistry to describe molecules that contain carbon atoms. So the active ingredients in “organic sunscreens” contain carbon-based molecules, while the active ingredients in “inorganic sunscreens” do not - they are molecules like titanium dioxide. Both types can help to prevent sunburn if used correctly - they just work in different ways.
Organic sunscreens, also known as chemical sunscreens, work by absorbing ultraviolet rays from the sun. Inorganic sunscreens, also known as physical sunscreens or sunblocks, work by reflecting those rays.
Most available brands are now a mix of both types.
UPF (Ultraviolet Protection Factor)
UPF refers to the amount of UVA & UVB rays blocked by apparel and fabrics.
Some facts about UPF:
UPF is a transmission test: A fabric is exposed to a UV source that simulates the sun's rays at noon. The amount of UV rays blocked by the fabric is measured by a device called a spectrophotometer. The UPF rating refers to how much Ultraviolet Radiation is blocked. For example, a UPF 50+ blocks 97.5% of the sun's UVA and UVB rays.
Darker colours are better UV absorbers than lighter colours - they have a higher UPF. Therefore, a black shirt will block more UV rays than a white shirt.
Beware of companies touting products with a UPF 100. UPF 50+ is the highest rating permitted by any National Standard in the world - including the new US Standard. Companies claiming higher UPF numbers are doing so for marketing purposes and are misleading consumers. UPF 100 does not mean it has twice the level of protection.
Manufacturers often use SPF & UPF interchangeably when promoting the sun protection their products offer. This is mainly because research shows that there is much confusion about what these terms mean. An SPF 15 rating is not the same as a UPF rating of 15 - the two numbers are not interchangeable. UPF is the correct reference and measurement for fabrics.
Just as a number of factors can influence the SPF ratings in sunscreens, the type of fabric, weave, colour, construction, humidity and wetness, stretch and wear and tear are factors that can also influence UV protection in fabrics. In order to obtain a UPF rating on any fabric, manufactures will need to submit a sample from each fabric colour and style for UV testing.
UPF Rating Standards
Sun protective clothing was largely originally developed in Australia. Sun protective clothing and UV protective fabrics in Australia now follow a lab-testing procedure regulated by an Australian federal agency ARPANSA. This standard was established in 1996 after work by Australian swimwear companies. The British standard was established in 1998. The NRPB (National Radiological Protection Board) forms the basis of the British Standards Institute. Using the Australian method as a model, the USA standard was formally established in 2001, and now employs a more stringent testing protocol: This method includes fabric longevity, abrasion/wear and wash ability. UPF testing is now very widely used on clothing and fabrics used for outdoor activities.
The original UPF rating system was enhanced in the United States by the ASTM (American Standards and Testing Methods) Committee at the request of the U.S. Food and Drug Administration (FDA) to qualify and standardize the emerging sun protective clothing and textile industry. The UPF rating system is gradually being adopted by interested apparel and textile/fabric manufacturers in the industry at large as a "value added" program to enhance consumer safety and consumer awareness.
What are UVA, UVB and UVC Rays?
The shortest-wavelength and most damaging portion of the UV spectrum. The ozone layer completely blocks out the UVC rays. Without the protection of the ozone layer, the sun's UVC radiation would threaten life on Earth.
The longest-wavelength portion of the UV band (in the range 315 nanometers to 400 nanometers), UVA is not blocked by the stratospheric ozone layer, and reaches the ground in relatively large amounts. It is considered the least damaging of the three, but far from harmless. UVA rays penetrate to the inner layer of the skin (dermis) where it can damage blood vessels, DNA, and compromise the skin's physical support system, contributing to premature aging and wrinkling of the skin. Recent studies show that it may be more damaging than originally thought.
UVB rays (in the range of 280 nanometers to 315 nanometers of the electromagnetic spectrum) are more damaging than UVA rays, but, because they are effectively blocked by the ozone layer (less than 1% of the sun's energy that reaches the surface), they are less abundant. UVB rays are more prevalent in summer. UVB light affects only the outer layer of the skin (epidermis). They are more energetic than UVA, cause sunburn much faster and are the single-most major cause of skin cancer.
Which offers the best sun protection - Sunscreen or UV Swimwear & UVClothing ?
At sun-togs we feel strongly that UV Clothing and UV Swimwear provide the highest and most assured levels of protection from the sun’s harmful UVA and UVB rays for the following reasons:
- Fabrics used in the manufacture of UV Clothing and UV Swimwear are UPF 50+ rated and generally offer superior broad spectrum (UVA and UVB) protection to the user when compared to sunscreens.
- Sunscreens can be easily under applied, not applied frequently enough or can rub off. Each formulation of sunscreen also has varying degrees of water resistance. So protection levels actually achieved are quite likely to be less than those advertised. There are also relatively few highly rated (SPF 50) broad spectrum sunscreens available.
- UV Clothing and UV Swimwear are immensely more practical, comfortable and convenient. Experience suggests that adults and especially children are happier to wear these. By contrast many people and children don’t like to frequently apply sticky, greasy or oily sunscreens.
- Many people, especially those with sensitive skin, eczema and other skin conditions have adverse skin reactions to some of the chemicals used in sunscreen. Wearing UV Clothing or Swimwear means that generally only the lower limbs, face and neck require additional protection with sunscreen.
- Our advice here at sun-togs is to use a good quality sunglasses, a good UV sun hat or swim hat for protection of the head, neck and face, a casual UV shirt and shorts or UV swim shirt and UV swim shorts (children also have the option of UV sun-suits) and then use a minimum SPF 30+ broad spectrum sunscreen (with high water resistance) for the face, neck and lower limbs.
Updated March, 2012