UL 94V Certification vs. UL 94 VTM Certification

In an ear­li­er blog con­cern­ing CAPLIN­Q’s UL Cer­ti­fi­ca­tion pol­i­cy, it was out­lined how CAPLINQ sup­ports its cus­tomers with the UL cer­ti­fi­ca­tion of poly­imide and oth­er tapes. This time, the dif­fer­ences between UL94 V‑0 and UL94 VTM‑0 will be described.

Certification Classification

ulvtm_coneFor tapes and oth­er thin mate­ri­als, the cer­ti­fi­ca­tion clas­si­fi­ca­tion typ­i­cal­ly used is UL94 VTM‑0. The UL94 V‑0 code is used for a self sup­port­ing mate­r­i­al. The prob­lem that aris­es with a very thin mate­r­i­al is that it may not burn but it will shrink or dis­tort as the flame is direct­ed to the sam­ple and if it can­not with­stand a ten sec­ond appli­ca­tion before in shrinks to the hold­ing clamp, so it will not be clas­si­fied as a 94V mate­r­i­al. Cas­es like this are what UL 94VTM is used for. You take a sheet 200mm X 50m and form a cone with it to per­form the flame test as shown in the fig­ure. Many thin mate­ri­als that will not burn but will shrink to the clamp and need VTM testing.

Vertical Testing of Thin Materials (VTM‑0, VTM‑1, VTM‑2)

This test is used for mate­ri­als that are thin, or are too flex­i­ble or may dis­tort, shrink or flex dur­ing ordi­nary ver­ti­cal test­ing. Pro­ce­dure: An 8x2 in spec­i­men is rolled lon­gi­tu­di­nal­ly around a 1/2 in diam­e­ter man­drel and taped on one end. When the man­drel is removed the spec­i­men forms a cone. The cone is sup­port­ed in a ver­ti­cal posi­tion and a flame is applied to the bot­tom of the spec­i­men. The flame is applied for three sec­onds and then removed until flam­ing stops at which time the flame is reap­plied for anoth­er three sec­onds and then removed. Two sets of five spec­i­mens are test­ed. The two sets are con­di­tioned under dif­fer­ent conditions.

Vertical Flame Test for Thin Materials

Ver­ti­cal Rating
for Thin
Materials
Require­ments
VTM‑0
  • Spec­i­mens must not burn with flam­ing com­bus­tion for more than 10 sec­onds after either test flame application.
  • Total flam­ing com­bus­tion time must not exceed 50 sec­onds for each set of 5 specimens.
  • Spec­i­mens must not burn with flam­ing or glow­ing com­bus­tion up to the spec­i­men hold­ing clamp.
  • Spec­i­mens must not drip flam­ing par­ti­cles that ignite the cotton.
  • No spec­i­men can have glow­ing com­bus­tion remain for longer than 30 sec­onds after removal of the test flame.
  • No spec­i­men shall have flam­ing or glow­ing com­bus­tion up to a mark 5 inch­es from the bot­tom of the specimen.
VTM‑1
  • Spec­i­mens must not burn with flam­ing com­bus­tion for more than 30 sec­onds after either test flame application.
  • Total flam­ing com­bus­tion time must not exceed 250 sec­onds for each set of 5 specimens.
  • Spec­i­mens must not burn with flam­ing or glow­ing com­bus­tion up to the spec­i­men hold­ing clamp.
  • Spec­i­mens must not drip flam­ing par­ti­cles that ignite the cotton.
  • No spec­i­men can have glow­ing com­bus­tion remain for longer than 60 sec­onds after removal of the test flame.
  • No spec­i­men shall have flam­ing or glow­ing com­bus­tion up to a mark 5 inch­es from the bot­tom of the specimen.
VTM‑2
  • Spec­i­mens must not burn with flam­ing com­bus­tion for more than 30 sec­onds after either test flame application.
  • Total flam­ing com­bus­tion time must not exceed 250 sec­onds for each set of 5 specimens.
  • Spec­i­mens must not burn with flam­ing or glow­ing com­bus­tion up to the spec­i­men hold­ing clamp.
  • Spec­i­mens can drip flam­ing par­ti­cles that ignite the cotton.
  • No spec­i­men can have glow­ing com­bus­tion remain for longer than 60 sec­onds after removal of the test flame.
  • No spec­i­men shall have flam­ing or glow­ing com­bus­tion up to a mark 5 inch­es from the bot­tom of the specimen.

For more infor­ma­tion of UL clas­si­fi­ca­tion or poly­imide tapes, vis­it us or con­tact us for more details.

About Chris Perabo

Chris is an energetic and enthusiastic engineer and entrepreneur. He is always interested in taking highly technical subjects and distilling these to their essence so that even the layman can understand. He loves to get into the technical details of an issue and then understand how it can be useful for specific customers and applications. Chris is currently the Director of Business Development at CAPLINQ.

8 thoughts on “UL 94V Certification vs. UL 94 VTM Certification

  1. Since most sol­der resists only have a V‑0 rat­ing because they have been test­ed ona FR4.0 car­ri­er I was won­der­ing if a sol­der rests for flex that passed VTM‑0 on poly­imide would be con­sid­ered more flame resis­tant than a reg­u­lar Sol­der­mask on FR4.0?

  2. May I know the dif­fer­ences between V‑0 and HF‑1 rat­ing when we test­ed to UL 94 for ther­mal insu­la­tion made from NBR (Nitrile Rubber)?
    Because I checked on UL list­ed direc­to­ry with the same mate­r­i­al (NBR) but you have 2 results V‑0 and HF‑1 also.
    Do you have any com­par­i­son which is better?
    When we have to use V‑0 rat­ed and when HF‑1 rated?

  3. UL94 is the stan­dard for safe­ty of flam­ma­bil­i­ty of plas­tic mate­ri­als for parts in elec­tri­cal equip­ment and acces­sories. There are dif­fer­ent ver­sions of this stan­dard for dif­fer­ent type of mate­ri­als where­of UL94 V is the most com­mon, how­ev­er this test is not suit­able for all types of plas­tic mate­ri­als. For some spe­cif­ic cas­es a sep­a­rate method and set of clas­si­fi­ca­tions has been cre­at­ed. For exam­ple, the UL94 HBF stan­dard is specif­i­cal­ly for foams and the UL94 VTM stan­dard is for thin mate­ri­als. HF‑1 is one of the pos­si­ble clas­si­fi­ca­tions from the UL94 HBF standard.

  4. I am look­ing for a fire­proof bag and found one that stat­ed… “It is made of dou­ble lay­ered non-itchy sil­i­cone coat­ed fiber­glass which stands up the tem­per­a­ture up to 2000℉.It has been passed by SGS TEST(UL94 VTM‑0 Cer­ti­fied). ” Is this good or bad? What type of cer­ti­fi­ca­tion should I look for to keep impor­tant papers safe from fire and water?

  5. The fire­proof bag you described seems to have some promis­ing fea­tures, but it’s essen­tial to under­stand the cer­ti­fi­ca­tions and mate­ri­als to ensure it will ade­quate­ly pro­tect your impor­tant papers from fire and water damage.

    Here are some key points to consider:

    Mate­r­i­al: The bag is made of dou­ble-lay­ered non-itchy sil­i­cone coat­ed fiber­glass, which is a com­mon fire-resis­tant mate­r­i­al. This is a good sign as it sug­gests the bag should with­stand high temperatures.

    Tem­per­a­ture Rat­ing: The bag claims to with­stand tem­per­a­tures up to 2000℉. This is an excel­lent tem­per­a­ture rat­ing and should pro­vide sub­stan­tial pro­tec­tion for your doc­u­ments in most house fires, as typ­i­cal house fires rarely exceed this temperature.

    SGS Test and UL94 VTM‑0 Cer­ti­fied: The fact that it has passed SGS test­ing and is UL94 VTM‑0 Cer­ti­fied is a pos­i­tive sign. SGS is a rep­utable glob­al test­ing and cer­ti­fi­ca­tion orga­ni­za­tion, and UL94 VTM‑0 is a fire test­ing stan­dard for flam­ma­bil­i­ty of plas­tic mate­ri­als. A VTM‑0 rat­ing indi­cates the mate­ri­al’s high resis­tance to burn­ing, which is ben­e­fi­cial for a fire­proof bag.

    Water Resis­tance: While the bag is pri­mar­i­ly adver­tised as fire­proof, you should also con­sid­er its water resis­tance. Many fire­proof bags are also designed to be water-resis­tant, which can be impor­tant in case your doc­u­ments are exposed to water dur­ing fire­fight­ing efforts.

    Size and Capac­i­ty: Ensure the bag is large enough to hold all the impor­tant doc­u­ments you want to pro­tect. Some bags are larg­er than oth­ers, so choose one that suits your needs.

    Addi­tion­al Fea­tures: Some fire­proof bags come with extra fea­tures like a car­ry­ing han­dle, shoul­der strap, or inner pock­ets for bet­ter organization.

    When choos­ing a fire­proof bag to pro­tect impor­tant doc­u­ments from fire and water dam­age, look for cer­ti­fi­ca­tions like UL94 VTM‑0 or UL72 for fire resis­tance. Also, con­sid­er inde­pen­dent test­ing from rep­utable orga­ni­za­tions like SGS. Make sure the bag meets your size and capac­i­ty require­ments, and if water resis­tance is essen­tial, check for that fea­ture as well.

    Keep in mind that no fire­proof bag can pro­vide absolute pro­tec­tion against all con­di­tions, but a high-qual­i­ty bag with the right cer­ti­fi­ca­tions should sig­nif­i­cant­ly increase the chances of pre­serv­ing your impor­tant doc­u­ments in case of a fire or water-relat­ed incident.

  6. The 7‑day con­di­tion­ing process for UL94V‑0 test­ing is an impor­tant step in assess­ing the fire resis­tance of plas­tic mate­ri­als and prod­ucts. UL94 is a stan­dard estab­lished by Under­writ­ers Lab­o­ra­to­ries (UL), a glob­al­ly rec­og­nized safe­ty test­ing and cer­ti­fi­ca­tion orga­ni­za­tion. The UL94V‑0 rat­ing is a spe­cif­ic clas­si­fi­ca­tion with­in this standard.

    The pur­pose of the 7‑day con­di­tion­ing process is to sim­u­late the effects of aging on a plas­tic mate­r­i­al before sub­ject­ing it to flam­ma­bil­i­ty test­ing. This process helps ensure that the mate­ri­al’s fire resis­tance remains con­sis­tent over time and is not sig­nif­i­cant­ly affect­ed by envi­ron­men­tal fac­tors or aging. Here’s why it’s necessary:

    Real­is­tic Test­ing: Mate­ri­als, espe­cial­ly plas­tics, can change their prop­er­ties over time due to expo­sure to envi­ron­men­tal fac­tors like humid­i­ty, tem­per­a­ture fluc­tu­a­tions, and UV radi­a­tion. These changes could affect a mate­ri­al’s flam­ma­bil­i­ty char­ac­ter­is­tics. The 7‑day con­di­tion­ing process pro­vides a con­trolled envi­ron­ment to age the mate­r­i­al in a way that’s sim­i­lar to real-world conditions.

    Con­sis­ten­cy: By sub­ject­ing the mate­r­i­al to a con­sis­tent aging process, the test­ing aims to ensure that the mate­ri­al’s fire resis­tance remains con­sis­tent from one batch to anoth­er and over time. This helps man­u­fac­tur­ers and con­sumers have con­fi­dence in the mate­ri­al’s performance.

    Safe­ty: The UL94V‑0 rat­ing is the high­est lev­el of fire resis­tance with­in the UL94 stan­dard. Mate­ri­als that achieve this rat­ing are deemed self-extin­guish­ing and are less like­ly to con­tribute to the spread of flames in case of a fire. To main­tain safe­ty stan­dards, it’s cru­cial that the mate­ri­al’s fire resis­tance remains stable.

    Reli­a­bil­i­ty: UL94V-0-rat­ed mate­ri­als are often used in appli­ca­tions where fire safe­ty is crit­i­cal, such as elec­tron­ics and elec­tri­cal equip­ment. The 7‑day con­di­tion­ing process helps ensure the reli­a­bil­i­ty of these mate­ri­als in such applications.

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