How Bicycle Helmets are tested

Summary: This page describes the lab tests that bike helmets must pass to meet the CPSC standard. There is other testing related to lead content that we do not cover. CPSC has a video of this testing up on their Web site.

The testing to certify attractive bicycle helmets to the US Consumer Product Safety Commission's standard for bicycle helmets can be described in six steps.

1. Samples required
The lab must procure samples of the helmet model. Full compliance testing requires 11-16pcs samples. The lab also needs a number from the manufacturer called the Helmet Positioning Index (HPI). It specifies the measurement to place the helmet correctly on the headform.

2. Marking
The lab technician puts the first sample on a test headform the right size to fit it. The headform is mounted upright on a stand, usually on a flat table. The helmet is adjusted using the HPI and then a 5 kilogram (10.x pound) cloth bag filled with lead shot is placed on it to compress any fitting foam inside. A marker on a stand is adjusted to the right level, using a measurement from a table in the standard that varies by helmet size. With the marker against the helmet the test line is marked by either rotating the helmet or sliding the marker stand around it. Each sample is marked in turn.
The lab test impacts must all be centered on or above the test line. The area below the line is not tested, although the "footprint" of an impact centered on the test line will extend below the line, and the helmet is not likely to pass if there is no material there. To get an idea of where the test line falls, you can take a medium sized helmet and mark the line xx mm below the top. Put that helmet on your head and you will see that the test line is probably higher than it should be, and the area of the helmet tested is really not large enough. The Snell Memorial Foundation's bicycle helmet standard has a lower test line. Even the old ANSI standard adopted in 1984 had a lower test line.

3. Conditioning
Helmets are tested hot, wet, cold and room temperature. Four samples are heated to Four samples are chilled to Four samples are soaked in water. Four samples are tested dry and room temperature.

4. Strap test
Next comes the strap strength and "roll off" testing. Here is one test rig. There are other designs, but they all functions the same.

5. Drop tests
The helmet is now ready for drop testing. It is strapped onto a head form, held upside down on a test rig that guides its fall onto an anvil. This rig in the CPSC lab is a monorail, and the drop is guided by a single rail. Others use two parallel wires (twin wire).

The lab technician raises the helmet and headform up until the top of the helmet is a specified distance from the anvil below. A trigger lets the helmet drop in free fall until the helmet hits the anvil. The velocity of the drop is checked just before the impact to ensure that the speed was correct. An instrument called an accelerometer measures g's in the center of the headform. If the helmet works well, the g's are low--probably below 200, and in the better helmets below 150. If the g's exceed 300, the helmet fails. The testing is on three anvils of different shapes:
The flat anvil is used with a 2 meter drop. The helmet and headform are traveling at 14 mph at impact.

The hemispheric anvil shown below, about the shape of a grapefruit, is used with a 1.2 meter drop. (The point load makes it a severe test.) The helmet and headform are traveling 11 mph at impact.

The hazard or curbstone anvil is rounded like the edge of a curb. It is another severe test, and the drop is 1.2 meters (11 mph).

If the drop speeds seem too low to you, please see our page on limits of helmet protection, where we explain them. We think they are adequate. If improvement can be made, lowering the g's permitted would reduce injuries more than raising the drop height, but you may need to review the physicals of a fall to see why.

6. Records
The CPSC standard requires the lab to keep records of the testing. That includes data on the helmet and data on performance.

Pass or Fail
The bottom line is that the helmet must pass all of the tests described above. If it fails on any of them, it cannot be certified to the standard. You don't meet a standard "except for . . ." A failure on any element of the tests is a complete failure.

Increasingly strict environmental protection system makes companies feel at a loss

In the past two years, we have been unable to speed up the transformation of industrial coal fired boilers in terms of environmental protection to catch up with the speed of change in environmental policy. Basically, many boilers are undergoing a series of "build-rebuild -again", frequently changes in policies often make enterprises feel at a loss what to do, and last they are faced with being shut down". Recently, at the working meeting of "research on ultra-low emission technology of coal-fired boilers" Organized by China urban heating association, many enterprise personages attending the meeting talked about the ultra-low emission transformation work of coal-fired heating boilers promoted in the past two years.

With the increasingly urgent situation of air pollution prevention and control, around the implementation of the winter clean heating plan in the northern region, China has set off a wave of elimination of coal-fired boilers and ultra-low emission reform. Following the release of the latest “Boiler Air Pollutant Emission Standard” (GB13271-2014) on May 16, 2014, Beijing, Shanghai, Tianjin, Chongqing, Guangzhou, and other places successively revised and revised the local boiler air pollutant discharge standards. In addition, Guangdong, Shaanxi, Hebei, Shandong, Hangzhou and other places have also issued the "Consultation Draft" for local boiler air pollutant discharge standards. According to complete statistics, more than 10 provinces including Gansu, Henan, Shandong, and Jiangsu have successively announced subsidies for industrial coal fired boilers.

industrial coal fired boilers

In order to achieve the goal of air pollution control as soon as possible, all regions are doing their best to carry out comprehensive control of industrial coal fired boilers. Accelerating the elimination or replacement of small coal-fired boilers, and at the same time, with the higher than the national standards and requirements for boiler air pollutants discharge, carry through boiler registration system and online control, etc. We have given great impetus to ultra-low emission renovation of medium and large coal-fired boilers.

In fact, the above standards are far lower than current national standards for the emission of air pollutants from coal-fired boilers and even far lower than the national standards for the mission of gas boilers. It’s said that the region also implemented the source control strategy, the boiler coal sulfur content, ash content and other indicators have also been strictly limited. At the same time, in order to meet the needs of environmental protection in a special period time, we have also introduced more stringent emergency plans for emission targets. Some places even proposed that industrial coal fired boilers with less than 100 tons of steam should be shut down, and this is not an isolated case across the country.

Vertical Expander Machine for 3meters coil tube

Hydraulic Vertical Expander Features:

-Working Length: 600mm; 800mm; 1000mm; 1200mm; 1600mm;2000mm, 2500mm; 3000mm

-The products below 1600mm equipped with Opening by Manual-Door or with Double-Station rotary workable , the products above 1600mm with 84°

inclined Turnover-Door and Manual-Open door is required by products below 1200mm workpiece;

-Products long than 1600mm will be equipped with internal oil cylinder type




Purpose:

Hydraulic Vertical Expander is specailly used to expand Fin Heat-Exchanger.

The Process of Expanding Pipe and Flaring on one shot in a working Cycle.



Vertical Expander Features:

-Working Length: 600mm; 800mm; 1000mm; 1200mm; 1600mm;2000mm, 2500mm; 3000mm

-The products below 1600mm equipped with Opening by Manual-Door or with Double-Station rotary workable , the products above 1600mm with 84°

inclined Turnover-Door and Manual-Open door is required by products below 1200mm workpiece;

-Products long than 1600mm will be equipped with internal oil cylinder type




Purpose:

Hydraulic Vertical Expander is specailly used to expand Fin Heat-Exchanger.

The Process of Expanding Pipe and Flaring on one shot in a working Cycle.

HAND-HELD LASER WELDING MACHINE

Compared with traditional welding, hand-held laser welding machine improves efficiency by more than 50%, smooth and even. It is easy to grind or does not need to be polished after welding. Now it has debuted at the C position of the laser circle. However, while holding the convenience of hand-held welding equipment, we should put laser safety first in the equipment!

According to the data, due to improper use of the operator or product quality, many safety accidents have occurred: some leaked light from the welding head burned the leg; some were stray laser damage to the user's fundus retina; some were ignited by the reflected laser In addition, the surrounding flammable materials cause fires, etc., and its impact causes users to suffer for life, and manufacturers will also face huge claims. The source of all these accidents reflects the hidden dangers behind the current explosion of handheld welding equipment, the safety measures of welding equipment are not reasonable enough, and users have not received good safety training.

01、Popularization of knowledge: rigorous training before going to work
Educate and train the staff who operate the handheld fiber laser welding machine to make the operator understand the potential risks that may appear when operating the handheld laser welding equipment, suspend the appropriate laser safety exercise for the operator, and emergency treatment methods when the risk is presented. Furthermore, the management and use of lasers must be terminated by professional (vocational) personnel, and untrained and educated personnel may not open and use laser machines without authorization. The relevant person in charge of Shenzhen Minglei Laser Equipment Co., Ltd. suggested that when the machine is delivered to the customer, it is necessary to strictly carry out standardized operation training and paste the operation requirements in a conspicuous place on the operation site. For the machine to operate normally, it is necessary to open the host enable switch and hand. Hold the power switch of the gun head and press the three switches of the light emitting button to prevent accidental accidental injury. When the machine is delivered to the customer, it is necessary to strictly carry out standardized operation training and paste the operation requirements in a conspicuous place on the operation site.


02、Anti-beam radiation: wear radiation protective glasses and protective clothing
As we all know, the laser of the laser welding machine is the light energy radiation emitted by the excitation and is a high-intensity light. The laser light emitted by the laser source is generally considered to be free from physical harm when it is not in contact or invisible; but The laser welding machine will cause ionizing radiation and stimulated radiation during the welding process. This induced radiation will not affect the eyes and the body.

Although the laser beam is very small, the operator generally likes to stare at the beam of the welding machine, but if the sparks produced by cutting for a long time are harmful to the eyes, there will be a tingling sensation. The retina is a very sensitive organ, so the operator must wear a pair of radiation protection glasses under the condition of long-term viewing light source.

However, according to national safety standards GB 7247-1987 and GB 7247-1995 "Radiation Safety of Laser Products, Equipment Classification, Requirements and User's Guide", after calculation, hand-held welding equipment made with fiber lasers is used when the power exceeds 1000W People need full body protection. Just one pair of glasses is not enough, because naked skin will suffer burns. Therefore, during the operation, the operator should wear protective clothing to protect his safety to the greatest extent.


03、Working environment: strict compliance with hygiene standards
A large amount of ozone and oxynitride will be generated during the laser welding process; especially the ozone concentration far exceeds the reference health standard, which has a great impact on human health.

Therefore, there must be a good ventilation device at the work site to discharge harmful gases and metal dust. In addition to this, in addition, fire prevention equipment must be provided, such as sand boxes, fire extinguishers, fire hydrants, buckets, etc. The distance of flammable materials from the welding place shall not be less than 5m. If the specified distance cannot be met, it can be properly covered with asbestos board, asbestos cloth, etc. to prevent Mars from falling into flammable objects. The distance between explosive materials and welding station shall not be less than 10m.


04、Equipment selection: Quality is most important
According to laser safety standards: such as the international standard IEC 60825-1 and the national standard GB7247.1-2012, etc., handheld laser welding equipment belongs to the highest safety level (level IV) high-power laser equipment. Therefore, when an unknown object enters the optical path, the automatic stop of the laser power is a mandatory function.

Why is there a range hood in the kitchen and an additional roof exhaust fan?

The kitchen is a place for many people who love to cook. It is also a place with a lot of oil fume. In order to prevent the kitchen from having too much oil fume, many people will choose to install a range hood in the kitchen to exhaust the oil fume go with.

However, the function of the range hood is not powerful enough to exhaust all the fumes produced by the kitchen. In order to reduce the workload of the range hood, a roof exhaust fan can be installed in the kitchen. The existence of the exhaust fan is to assist the range hood to exhaust the kitchen fumes as much as possible.

When there are friends at home, you need to prepare food to entertain them, which will inevitably increase the amount of oil smoke in the kitchen. The hood can't always drain the oil fume in time. If there is an exhaust fan to help, then you can make the kitchen fume more.

Why choose an exhaust fan over other tools? This is closely related to the two major functions of the exhaust fan. First of all, the exhaust fan has good ventilation, which can exhaust the indoor oil smoke and also introduce fresh air outside. Secondly, the exhaust fan also has a heat dissipation function, because it can exchange outdoor and indoor air, which can reduce the temperature of the kitchen.

Where should the exhaust fan be installed in the kitchen? It is recommended to install it near the range hood, which can not only have the double effect of exhausting fume, but also play a good role in heat dissipation.

In addition to installing an exhaust fan in the kitchen, attention should also be paid to the storage of the kitchen. You can install cabinets in the kitchen, or you can install a storage rack on the wall to store the dishes you usually use.