放射能防護服
“MT-30”Class-3 F.R.S (ウェット式)

MT-30”は、米国警察・消防の緊急即応部隊に認定されたCBRN Suit NFPA Class-3の防護服です。

優れた「 SPF 機能」を持つ繊維で作られております。固体はもちろん液体をも遮断 (liquid proof) しますが、通気性があり、空気を通す特殊な能力があるので、人体から発生する蒸気を外部に排出することができる、卓越した防護力と快適性の両方を備えた特殊なスーツです。
※CBRNとは、化学(Chemical)、生物(Biological)、放射性物質(Radiological)、核(Nuclear)を用いた兵器等の脅威
※NFPAとは、米国「National Fire Protection Association」の略称です。
NFPA 1994 : Standard on Protective Ensembles for First Responders to CBRN
※Terrorism Incidents(class1~4)
※SPF : Selectively Permeable Fabric(選択的浸透性の繊維)

○ 高い強度のファブリックと縫い目補強
○ 長い貯蔵寿命、非カーボン・ベースのテクノロジー
○ 気密ジッパーは、液体や蒸気を中に入れません
○ 耐久性の高いNomex(R)の手袋・ブーツが一体となっておりテーピングの手間が不要です
○ 呼吸には、面付マスクを使用します


(特徴)
1.ウェット式ですので、防護服を着たまま水を使った除染が可能です。
2.使い捨てではなく繰り返し使えますので大変経済的です。
3.人体から発する熱と蒸気を外部に発散できる特殊な生地を採用。



1.内部被爆予防について

通常、原子力施設では、ウェット式の防護システムが採用されています。 
その理由は除染(decontamination)ができるからです。ウェット式防護服の運用にはシャワー式の除染装置を併用します。汚染地域から清浄地域に移る境界線に除染装置を設置し、防護服やマスク、手袋、ブーツ等の装備を身につけたまま、シャワーで汚染物質を洗い流します。そして放射線量計が基準値以下を示したら防護服とマスク、その他の装備を脱ぎ、他所へ移動することが許可されます。 
そのため防護服に付着していた粉塵を吸い込み、内部被爆を引き起こす危険性は低いとされています。


2.繰り返し使用が可能
"MT-30"は、使い捨てではありません。破損や汚染がない限り除染・クリーニングのうえ、繰り返し何回も使用できますので、大変経済的です。

3.人体から発する熱と蒸気を外部に発散
"MT-30"には、ハイレベルのBreathable(通気性)があります。
成人男子は一時間あたり、休息時に50ml、重労働時に1リットル、全力疾走時にはほぼ最大の4リットルの汗を出します。我々の体は汗を出し蒸発させることで体温の上昇を調節しています。"MT-30"防護服はこの人体から発する熱と汗を防護服内部に閉じ込めず、通気性により適切に外部に排出します。着用者の快適性の向上と肉体的苦痛やストレスの軽減が図れます。


 ドライ式防護服の問題点

1.水を使う除染(decontamination )ができない。
現在福島原発の事故現場で大量に使われているのは、デュポン(TM)タイベック(不織布製使捨タイプ)で、「ドライ式」です。本来はアスベスト撤去作業といった屋内のドライエリアでの使用を想定した製品です。この防護服は、耐水圧力が1041mmで小雨程度をカバーする撥水性はありますが、本格的な耐水性は有りません。
大雨や長時間の降雨及び大量の水が掛かる場所や水中では、水に溶けた放射性物質が、防護服を通り抜け装着者の皮膚にまで浸透する危険があります。 放射能防護服として使えないことはありませんが、水を使う除染(decontamination )ができないため原子力施設での使用には不向きといえます。
 
2.ドライ方式は体内被曝を引き起こす危険性が高いといわれています。


ドライ方式が危険といわれるのは、作業終了後に汚染エリアから清浄エリアへ移る際に、シャワー等の水を使った除染ができないので、自分の防護服に付着した汚染物質を吸い込む可能性があるからです。
汚染エリアと清浄エリアの間にある脱衣所では沢山の作業員が汚染物の付着した防護服や、手袋、ブーツ、そしてマスク等を脱ぎます。 その後シャワー室に移動して体や髪に付いた汚染物質を洗い流して除染しますが、それに至るまでの僅かな脱衣の時間に汚染物質を呼吸と共に体内に入れてしまう恐れがあります。
一回あたりの量は微々たるものかもしれませんが、長期間繰り返すのは危険です。

3.熱中症の危険性
不織布製の防護服は、大変軽量で長時間着用しても疲労が少ないといったメリットがありますが、補強のために施したポリエチレン系のコーティングにより通気性がきわめて低く、体から発する熱や蒸気の発散が殆どできません。そのため梅雨や真夏シーズンには、熱中症・熱射病の危険が高くなります 。 
汚染エリアの作業現場で熱中症の症状が出た場合には、防護服、マスク共に外せません。ウェット式ではその場でシャワーや水道水、バケツの水をかけるなどにより体温を下げる応急措置を施すことが可能ですが、ドライ式では、まず清浄エリアまで移動させて脱衣、除染した後に応急措置を施すことになります。

4.使い捨てのコストパフォーマンス
デュポン(TM)タイベックは使い捨式ですので、トイレや休憩、食事のために休憩所等の清浄エリアに入るときは、その都度脱衣所で防護服一式を脱ぎ捨て、再び作業に出るときは、新品の防護服を着用します。 一日8時間程度の労働をする場合には、最低4回はトイレや休憩が必要です。一人当たり4着のタイベックと4セットの帽子、手袋、ブーツを消費します。またこれらの使い捨て装備品は、放射性廃棄物となります。 
一着・一セットあたりの単価は高くはありませんが、一人当たり、4着4セットを毎日消費することと、放射性廃棄物の処理コストを加えると決して安いコストでありません。

 

 

SUMMARY OF NFPA 1994 PROTECTIVE ENSEMBLES FOR FIRST
RESPONDERS TO CBRN TERRORISM INCIDENTS, 2007 EDITION


Introduction
The National Fire Protection Association (NFPA) Standard for Chemical, Biological, Radiological and Nuclear (CBRN) protective ensembles, NFPA 1994 was originally published in 2001. NFPA 1994 was revised in 2007 and sets performance and certification requirements for CBRN protective ensembles. The standard provides minimum design, testing and performance standards for outer garments intended to provide first responders skin, eye, feet, and face protection in the event of a CBRN terrorist incident. NFPA 1994 ensembles are not, however, for protection from flames, welding/cutting, molten metals, hot liquids, steam, electrical arc, thermal radiation, explosions or flash fire.

The original standard established three (3) levels of protection: Class 1, Class 2 and Class 3. In the newest edition, the highest level of protection, Class 1 was removed and addressed in NFPA 1991. The newer edition also added a fourth level offering specific protection against particulates including certain human disease-causing agents (pathogens), toxins or radiological dusts or mists. All of the NFPA 1994 levels of protection require a NIOSH-approved CBRN respirator.


Discussion
Class 1 totally encapsulating suits including self-contained breathing apparatus (SCBA) are specialized, high performance products used by highly trained hazardous material response teams. Class 1 suits are stressful, more likely to cause heat related disorders, cumbersome, difficult to don and doff, and the most difficult to use. Class 2 ensembles include a SCBA and provide liquid protection. A Class 2 ensemble is for IDLH atmospheres where potential health hazards from skin exposures are not life threatening or do not pose severe risks.
NFPA 1994 is not intended for fire fighting, and does not establish respiratory protection requirements involving CBRN terrorism agents. Understanding this standard is needed to assess the protective apparel for the Navy Installation Protection Program because NFPA 1994 applies across any of the areas of first response whether fire, security, law enforcement, or medical.


Summary
The following are the main issues addressed in the standard:

● NFPA 1994 provides performance standards for minimum levels of protection for first responders involving CBRN terrorism agents.

● NFPA 1994 establishes requirements for protective ensembles that are “designed for a single exposure wearing” at CBRN terrorism incidents.

● There are four (4) classes of protection: Class 1 (highest level), Class 2, Class 3, and Class 4.

● Class 1 ensembles are not addressed in NFPA 1994. Class 1 ensembles are covered in NFPA 1991, Standards for Vapor Protective Ensembles for Hazardous Materials Emergencies.

● Class 4 ensembles are for particulates, notably biological or radiological particulate agents such as anthrax spores.

● NIOSH CBRN-approved respirators are specified for Class 2 through Class 4 ensembles.

● Ensembles include a complete set of protective gear including the respirator specified by the manufacturer for the specified class of protection.

● Classes 1 through 4 NFPA ensembles are similar but not equivalent to OSHA/EPA Levels A, B, C and D personal protective equipment. The difference is NFPA specifies the performance specifications for the different levels of protection. Also, Class 4 protection requires a NIOSH-approved CBRN air-purifying respirator with much more strict protective apparel than OSHA Level D.

● Class 2 ensembles require an SCBA for responders in IDLH atmospheres.

● Class 3 ensembles are not for IDLH atmospheres and involve low levels of vapors or liquid hazards where air purifying respirators are permitted.

● All NFPA protective ensembles are certified completely as a Class and must include protection to the upper and lower torso, head, arms, legs, hands, wrists and feet and respiratory system.

● A third party certifies that a product demonstrates compliance with the testing and re-certification requirements of the standard which authorizes the manufacturer to use a label indicating the Class of protective ensemble.

● All respirators, SCBA, PAPR or APR for NFPA 1994 levels of protection, must be certified by NIOSH as CBRN compliant.

● Class 2 and Class 3 garments are tested for permeation resistance against HD mustard and GD Soman nerve agents, and for permeation resistance against liquid and gaseous industrial chemicals (using test agents).

● Class 4 garments are tested for resistance to liquid or bloodborne pathogens using a bacteriophage viral penetration test.

● Class 2, 3, and 4 ensembles must past liquid integrity tests under a shower spray while on a mannequin and other physical integrity tests against punctures and cut resistance.


COMPARISON OF DIFFERENT NFPA 1994 LEVELS OF PROTECTION

Class 1 Ensemble - Not addressed in NFPA 1994
For example,
Dupont Tychem(R) TK 612T, Class 1 Suit

Gas- and vapor-tight, fully encapsulating suit is intended for use in the worst-case circumstances where the substance(s) involved create an immediate threat with unidentified and unknown concentrations of contaminants. Provides the highest level of protection. Ensemble consists of a suit with attached gloves that totally encapsulates the wearer and breathing apparatus. Garment, visor, gloves, footwear and seams provide the highest level of permeation resistance against chemical and biological agents as well as from high-threat industrial chemical liquids and gases. Tychem(R) TK suit must be worn with a separate over-cover for abrasion, tear, cut, flame & puncture resistance.

● No measurable penetration or permeation.
● High levels of durability to abrasion, tearing, punctures and cuts.
● Includes all the protective equipment elements-visors, gloves, footwear and special seams.
o Expanded back
o Attached 3-layer gloves, outer, middle and inner gloves; for example Viton(R), Silver Shield(R)/4H, KEVLAR(R) knit
o Attached sock boots (sock boots must be covered with NFPA 1991 compliant outer boot)
o Outer boot flaps & faceshield, for example 40 mil PVC, 5 mil Teflon(R), 20 mil PVC
o Gas-tight zipper closure, double storm flaps, four exhaust valves (pressure demand)

Class 2 Ensemble for example Geomet Technologies’ DTAPS(R) (Disposable Toxicological Agent Protective System) The agent or threat has generally been identified and the actual release has subsided. A Class 2 ensemble protects responders at C/B terrorism incidents where it is necessary to provide vapor


protection with SCBA and where direct contact with liquid droplets is probable where victims are symptomatic but not able to walk:
● A “shower” test shows the suit will not allow penetration of water when sprayed from several directions.
● Garment, visor, gloves, footwear and seams must demonstrate permeation resistance to chemical warfare agents and liquid/gaseous toxic industrial chemicals at lower concentrations than in Class 1, and higher than Class 3.
● Demonstrated durability to abrasion and resistance to punctures and cuts.
● Garments, gloves and boots are designed for single use exposure at incidents involving CBRN terrorism agents.
● Not for flash fire protection - will burn and possibly melt which could increase burn injuries.

Chemical permeation test, for CWA: cumulative permeation in 1-hour in μg/cm2; for liquids and gaseous TICS, breakthrough time in mins (must be greater than 60 mins)

Liquid chemical warfare agents (CWA), 10g/m2
● Distilled sulfur mustard - HD
● Nerve agents - GD (Soman)
Liquid toxic industrial chemicals, 10g/m2
● Acrolein
● Acrylonitrile
● Dimethyl sulfate
Gases, 350 ppm
● Ammonia
● Chlorine
Man-In-Simulant-Test (MIST), Using an airborne test agent in a test chamber and measure leakage of the agent on 30 body locations under protective ensembles to determine a “protection factor.”
Chemical vapor testing
● Methyl salicylate (oil of wintergreen), 100 mg/m3
● Requires a minimum overall protection factor of 360
Visor
● Tested for
o Chemical permeation
o Bursting strength
o Puncture resistance
o Cold temperature bending
o Seam strength
o Pathogen resistance
Gloves
● Designed for single use with CBRN terrorism agents
● No less than five separate & distinct sizes
● Tested for:
o Liquid tight integrity & chemical permeation
o Cut and puncture resistance
o Cold weather performance
o Hand function
o Resistance to liquid or blood-borne pathogens
Footwear
● Tested for:
o Liquid tight integrity & permeation resistance
o Cut, puncture & abrasion resistance
o Slip resistance
o Resistance to liquid or blood-borne pathogens
Garment - other
● Tested for:
o Bursting strength
o Tear resistance
o Cold weather performance
o Seam strength
o Closure strength
o Resistance to liquid or blood-borne pathogens

 

Class 3 Ensemble, for example Dupont Tychem CPF3

Intended for use long after the release has occurred or in the peripheral zone of the release scene.
● Where hoods are provided, garment shall accommodate head protection meeting requirements of Type I, Class G helmets of ANSI Z89.1, Industrial Head Protection.
● Ensemble is certified with CBRN air-purifying respirator which covers the eyes, nose and mouth and which is specified by the manufacturer.
● Garments, gloves and boots are designed for single exposure at incidents involving CBRN terrorism agents
● Not for fire protection - may melt in flame and increase burn injuries

Chemical permeation test, for CWA: cumulative permeation in 1-hour in μg/cm2; for liquids and

Liquid chemical warfare agents, 10g/m2
● Distilled sulfur mustard - HD
● Nerve agents - GD (Soman)
gaseous TICS, breakthrough time in mins (must be greater than 60 mins)
Liquid toxic industrial chemicals, 10g/m2
● Acrolein
● Acrylonitrile
● Dimethyl sulfate
Gases, 350 ppm
● Ammonia
● Chlorine
Man-In-Simulant-Test (MIST), Using an airborne test agent in a closed chamber and measure leakage of the surrogate agent onto 30 body locations under protective ensembles
Chemical vapor testing
● Methyl salicylate (oil of wintergreen, a surrogate agent for mustard gas), 100 mg/m3
● Requires a minimum overall protection factor of 76
Visor
● Tested for
o Chemical permeation
o Bursting strength
o Puncture resistance
o Cold temperature bending
o Seam strength
Gloves
● Designed for single use for CBRN terrorism agents
● No less than five separate & distinct sizes
● Tested for:
o Liquid tight integrity & chemical permeation
o Cut, puncture & pathogen resistance
o Cold weather performance
o Hand function
Footwear
● Tested for:
o Liquid tight integrity & chemical permeation resistance
o Cut, puncture & abrasion resistance
o Slip resistance
o Pathogen resistance
Garment - other
● Tested for:
o Bursting strength
o Tear resistance
o Cold weather performance
o Evaporative heat transfer
o Seam strength
o Closure strength
o Resistance to liquid or blood-borne pathogens
Class 4 Ensemble
For situations involving potential exposure to biological aerosols or particles and low level radiological particles.
● Uses a test for Class 4 ensembles where test subjects wear the protective ensemble inside a chamber with fluorescent particles.
● The test subjects perform a series of exercises. Following the test, the ensemble is removed and a UV light is used to evaluate if any particles have penetrated the ensemble.
Gloves
● Designed for single use for CBRN terrorism agents
● No less than five separate & distinct sizes
● Tested for:
o Resistance to liquid or bloodborne pathogens
o Liquid tight integrity
o Cut, puncture & abrasion resistance
o Cold weather performance
o Hand function
Footwear and/or covers
● Tested for:
o Resistance to liquid or bloodborne pathogens
o Liquid tight integrity
o Cut, puncture & abrasion resistance
o Slip resistance


Conclusion
NFPA 1994 protective ensembles are the “gold standard” for personal protective clothing of first responders exposed to victims, or materials during assessment, extrication, rescue, triage, decontamination, treatment, site security, crowd management and force protection operations involving CBRN terrorism agents. With the newer, more comprehensive requirements and personal protective equipment performance criteria, protective ensembles will be needed based on the threat, criticality, vulnerability and hazard assessment. Use requirements for CBRN protective ensembles are specified in NFPA 1500, Standard on Fire Department Occupational Safety and Health Program. Future protective ensembles for approved CBRN ensembles for first responders will need to specify the Class for emergency management planning.




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