Yuav Ua Li Cas Xaiv Txoj Cai Fiber Cement Board Txiav Pom Hniav

Fiber cement board (FCB) tau dhau los ua cov khoom siv tseem ceeb hauv kev tsim kho vim nws lub zog siab, hluav taws kub tsis kam, dej tsis kam, thiab kav ntev. Txawm li cas los xij, nws qhov tshwj xeeb muaj pes tsawg leeg - sib xyaw Portland cement, ntoo fibers, silica xuab zeb, thiab cov khoom ntxiv - ua rau muaj teeb meem loj thaum txiav: siab brittleness (nruj mus rau ntug chipping), silica cov ntsiab lus siab (tsim ua pa ua pa crystalline silica plua plav, muaj kev phom sij rau kev noj qab haus huv tswj hwm los ntawm OSHA 1926.1153), thiab abrasive zog (ua kom nrawm nrawm). Rau cov tuam txhab, cov neeg cog lus, thiab cov neeg tsim khoom, xaiv txoj cai saw hniav tsis yog tsuas yog ua kom muaj kev ua haujlwm zoo thiab zoo; nws kuj yog hais txog kev ua raws li cov qauv kev nyab xeeb, tiv thaiv cov neeg ua haujlwm kev noj qab haus huv, thiab zam cov khoom siv puas tsuaj.

Cov kab lus no tau ua txhaum txoj kev xaiv los ntawm kev txheeb xyuas cov khoom txiav (FCB), pom cov ntawv qhia tshwj xeeb, cov khoom siv sib xws, cov xwm txheej tsim khoom, thiab cov xwm txheej ntawm daim ntawv thov-tag nrho ua raws li cov kev cai ntawm OSHA cov txheej txheem respirable crystalline silica thiab kev lag luam zoo tshaj plaws.

2. Kev soj ntsuam ntawm cov khoom txiav: Fiber Cement Board (FCB) Cov yam ntxwv

Thawj kauj ruam hauv kev xaiv cov saw hniav yog kom nkag siab txog cov khoom ntawm cov khoom, raws li lawv ncaj qha txiav txim siab cov saw hniav qhov yuav tsum tau ua.

2.1 Core Composition thiab Txiav Kev Sib Tw

Fiber cement boards feem ntau muaj 40-60% Portland cement (muab lub zog), 10-20% ntoo fibers (txhim kho toughness), 20-30% silica xuab zeb (kev txhim kho ntom), thiab me me ntawm additives (txo kom tawg). Qhov kev sib xyaw no tsim peb qhov kev sib tw tseem ceeb:

• Silica hmoov av tiam: Silica xuab zeb nyob rau hauv FCB ​​tso respirable crystalline silica hmoov av thaum txiav. OSHA 1926.1153 tswj hwm cov plua plav nruj (xws li, lub tshuab tso pa tawm hauv zos / LEV), yog li cov saw hniav yuav tsum sib haum nrog cov khoom siv plua plav kom txo cov plua plav tawm.
• Brittleness thiab ntug chipping: Cov cement-sand matrix yog nkig, thaum ntoo fibers ntxiv me ntsis yooj. Tsis sib luag txiav quab yuam los yog tsis tsim cov hniav tsim tau yooj yim ua rau ntug chipping, cuam tshuam rau lub rooj tsavxwm installation thiab zoo nkauj.
• Kev puas tsuaj: Silica xuab zeb ua raws li abrasive, accelerating saw hniav hnav. Cov saw hniav lub matrix thiab cov khoom siv hniav yuav tsum muaj kev hnav tsis kam ua kom lub neej ntev.

2.2 Lub cev muaj zog cuam tshuam rau kev xaiv saw hniav

• Qhov ntom: FCB ceev li ntawm 1.2 mus rau 1.8 g / cm³. Cov boards siab dua (piv txwv li, sab nrauv phab ntsa panels) yuav tsum tau pom cov hniav nrog cov ntaub ntawv tawv tawv (xws li, pob zeb diamond lossis tungsten carbide) kom tsis txhob dulling sai.
• Thickness: Feem ntau FCB thicknesses yog 4 hli (sab hauv partitions), 6-12 hli (sab nrauv cladding), thiab 15-25 hli (cov qauv vaj huam sib luag). Thicker boards xav pom cov hniav uas muaj peev xwm txiav qhov tob thiab nruj matrices los tiv thaiv cov hniav deflection thaum txiav.
• Nto tiav: Smooth-surface FCB (rau cov ntawv siv kho kom zoo nkauj) yuav tsum tau pom cov hniav nrog cov hniav zoo thiab cov txheej tiv thaiv kev sib txhuam kom tsis txhob khawb ntawm qhov chaw, thaum rough-surface FCB (rau kev siv cov qauv) tso cai rau cov hniav sib tsoo ntau dua los txhim kho kev ua haujlwm.

3. Pom Hniav Specifications: Qhov tseem ceeb Parameters rau Fiber Cement Board txiav

Raws li FCB tus yam ntxwv thiab OSHA cov qauv (xws li, txoj kab uas hla ntawm txoj kab uas hla txwv rau kev tswj plua plav), cov saw hniav hauv qab no tsis tuaj yeem sib tham tau rau kev ua haujlwm zoo thiab ua raws.

3.1 Hniav txoj kab uas hla: Kev nruj nruj nrog ≤8 nti

Raws li ob qho tib si OSHA 1926.1153 Table 1 thiab cov ntaub ntawv kev coj ua zoo tshaj plaws ntawm cov cuab yeej,handheld fais fab saws rau FCB txiav yuav tsum siv cov hniav nrog ib txoj kab uas hla ntawm 8 ntiv tes los yog tsawg dua. Qhov kev xav tau no tsis yog arbitrary:

• Plua plav collection compatibility: FCB txiav cia siab rau lub tshuab tso pa tawm hauv zos (LEV). Cov hniav loj dua 8 ntiv tes yuav dhau ntawm LEV system lub peev xwm airflow (OSHA mandates ≥25 cubic feet ib feeb [CFM] ntawm airflow ib nti ntawm cov hniav txoj kab uas hla). Piv txwv li, 10-nti hniav, yuav xav tau ≥250 CFM-ntau tshaj li cov khoom siv tes tuav lub peev xwm LEV-ua rau tsis muaj kev tswj xyuas cov plua plav tawm.
• Kev nyab xeeb ua haujlwm: Cov hniav me me (4-8 ntiv tes) txo qhov pom qhov sib hloov inertia, ua kom yooj yim rau kev tswj thaum tuav tuav, tshwj xeeb tshaj yog rau kev txiav ntsug (xws li, sab nrauv phab ntsa panels) los yog precision txiav (xws li, qhov rais qhib). Cov hniav loj dua ua rau muaj kev pheej hmoo ntawm cov hniav deflection lossis kickback, ua rau muaj kev nyab xeeb.

Cov kev xaiv dav dav rau FCB txiav: 4 ntiv tes (cov saw me me rau kev txiav nqaim), 6 ntiv tes (qhov dav dav FCB ​​txiav), thiab 8 ntiv tes (thick FCB panels, mus txog 25mm).

3.2 Hniav Matrix Khoom: Ntsuas Rigidity thiab Kub Ua Haujlwm

Lub matrix ("lub cev" ntawm cov saw hniav) yuav tsum tiv taus FCB qhov abrasion thiab tshav kub generated thaum txiav. Ob yam khoom tseem ceeb yog siv:

• Hardened hlau (HSS): Haum rau kev txiav qis qis (piv txwv li, kev tsim kho ntawm qhov chaw kov-ups). Nws muaj qhov zoo rigidity tab sis tsis tshua muaj kev kub ntxhov-ntev ntev tuaj yeem ua rau matrix warping, ua rau tsis sib xws. HSS matrices yog tus nqi zoo tab sis yuav tsum tau hloov cov hniav ntau zaus rau cov khoom ntim ntau.
• Carbide-tipped steel: Zoo tagnrho rau high-volume txiav (xws li, Hoobkas prefabrication ntawm FCB panels). Cov txheej txheem carbide txhim kho kev hnav tsis kam, thaum cov tub ntxhais hlau tuav rigidity. Nws tuaj yeem tiv taus kev txiav tsis tu ncua ntawm 500+ FCB panels (6mm tuab) yam tsis muaj kev sib hloov, ua raws li kev xav tau ntawm kev tsim khoom.

3.3 Hniav tsim: Tiv thaiv chipping thiab txo plua plav

Cov hniav tsim ncaj qha cuam tshuam rau kev txiav zoo (ntug smoothness) thiab tsim cov hmoov av. Rau FCB, cov hniav ntaws hauv qab no yog qhov tseem ceeb:

• Cov hniav suav: 24-48 hniav ib hniav. Cov hniav tsawg (24-32 cov hniav) yog rau tuab FCB (15-25mm) los yog ceev txiav-cov hniav tsawg dua txo kev sib txhuam thiab kub tab sis yuav ua rau me me chipping. Cov hniav suav siab (36-48 cov hniav) yog rau nyias FCB (4-12mm) los yog cov npoo du-ntau cov hniav faib txiav quab yuam sib npaug, txo qis.
• Cov hniav zoo li: Alternate top bevel (ATB) los yog triple-chip grind (TCG). ATB cov hniav (nrog rau lub kaum sab xis) yog qhov zoo tagnrho rau kev txiav du ntawm cov ntaub ntawv nkig zoo li FCB, raws li lawv hlais los ntawm cov cement matrix yam tsis tau tsoo cov npoo. TCG cov hniav (ib qho sib xyaw ntawm cov npoo tiaj thiab beveled) muab kev txhim kho kom ruaj khov rau abrasive FCB, ua rau lawv tsim nyog rau cov khoom ntim siab.
• Cov hniav sib nrug: Qhov dav dav (≥1.5mm) yog pom zoo kom tiv thaiv plua plav clogging. FCB txiav tsim cov hmoov av zoo; nqaim qhov sib nrug ntawm cov hniav tuaj yeem cuam tshuam cov plua plav ntawm cov hniav, ua kom muaj kev sib txhuam thiab txo kev txiav ceev. Qhov dav dav tso cai rau cov plua plav kom dim ntawm kev ywj pheej, ua raws li LEV system plua plav sau.

3.4 Txheej: Txhim kho kev ua haujlwm thiab kev ua neej nyob

Anti-kev sib txhuam coatings txo cov cua sov buildup thiab plua plav adhesion, txuas hniav lub neej thiab txhim kho tej smoothness. Cov txheej txheem ntau rau FCB pom cov hniav:

• Titanium nitride (TiN): Kub-xim txheej uas txo kev sib txhuam los ntawm 30-40% piv rau cov hniav tsis muaj coated. Haum rau kev txiav FCB ​​dav dav, nws tiv thaiv plua plav los ntawm kev ua raws li cov hniav, txo lub sijhawm ntxuav.
• Pob zeb diamond zoo li carbon (DLC): Ultra-nyuaj txheej (hardness ≥80 HRC) uas tiv taus abrasion los ntawm silica xuab zeb. DLC-coated hniav tuaj yeem kav ntev li 2-3 zaug ntev dua TiN-coated hniav, ua rau lawv raug nqi rau cov khoom ntim siab FCB.

4. Cov khoom sib txuam: Aligning Saw Blades nrog txiav tshuab

Cov hniav zoo nkauj tsis tuaj yeem ua tau zoo yam tsis muaj cov cuab yeej txiav. Raws li OSHA cov lus qhia, FCB txiav cia siab rauhandheld fais fab saws nrog integrated plua plav tswj systems-xws li lub qhov cua hauv zos (LEV) lossis cov tshuab xa dej (txawm tias LEV nyiam rau FCB kom tsis txhob ntub cov slurry buildup).

4.1 Cov Khoom Siv Tseem Ceeb: Handheld Power Saws nrog LEV Systems

OSHA txoj cai uas tuav cov saws rau FCB txiav yuav tsum tau nruab nrogkev lag luam muaj plua plav sau tshuab(LEV) uas ua tau raws li ob lub ntsiab lus tseem ceeb:

• Airflow muaj peev xwm: ≥25 CFM ib nti ntawm cov hniav txoj kab uas hla (piv txwv li, ib tug 8-nti hniav yuav tsum ≥200 CFM). Lub saw hniav txoj kab uas hla yuav tsum phim lub LEV system lub airflow-siv ib tug 6-nti hniav nrog ib tug 200 CFM system yog tau (feem ntau airflow txhim kho plua plav sau), tab sis ib tug 9-nti hniav nrog tib lub cev yog tsis raws li txoj cai.
• Lim efficiency: ≥99% rau cov plua plav ua pa. LEV system lub lim yuav tsum ntes silica plua plav kom tiv thaiv cov neeg ua haujlwm raug; cov saw hniav yuav tsum tau tsim los coj cov plua plav mus rau qhov system lub shroud (xws li, concave blade matrix uas funnels plua plav mus rau hauv qhov chaw nres nkoj).

Thaum sib piv saw hniav rau handheld saws, xyuas cov hauv qab no:

• Arbor loj: Lub saw hniav qhov chaw nruab nrab (arbor) yuav tsum sib phim lub saws spindle txoj kab uas hla (qhov ntau thiab tsawg: 5/8 nti lossis 1 nti). Lub arbor tsis sib haum ua rau cov hniav wobble, ua rau tsis sib xws thiab muaj plua plav ntau ntxiv.
• Ceev compatibility: Pom cov hniav muaj qhov siab tshaj plaws kev sib hloov ceev (RPM). Handheld saws rau FCB feem ntau ua haujlwm ntawm 3,000-6,000 RPM; cov hniav yuav tsum tau ntsuas tsawg kawg ntawm qhov pom qhov siab tshaj plaws RPM (piv txwv li, cov hniav ntsuas rau 8,000 RPM muaj kev nyab xeeb rau 6,000 RPM pom).

4.2 Cov khoom siv thib ob: Kev xa dej (rau cov xwm txheej tshwj xeeb)

Thaum LEV yog qhov zoo dua rau FCB txiav, cov khoom xa dej (ua ke rau hauv cov saw saws tes) tuaj yeem siv rau sab nraum zoov, siab-ntim txiav (xws li, sab nrauv phab ntsa vaj huam sib luag). Thaum siv cov txheej txheem dej:

• Pom hniav khoom: Xaiv cov khoom tiv thaiv corrosion (xws li stainless hlau-coated carbide) kom tiv thaiv xeb los ntawm dej raug.
• Cov hniav txheej: Zam cov txheej txheem dej-soluble; TiN lossis DLC txheej yog dej-tiv taus thiab tswj kev ua haujlwm.
• Slurry tswj: Lub sawb yuav tsum tau tsim kom txo qis slurry splatter (xws li, ib tug serrated ntug uas lov cov plua plav ntub dej), vim slurry tuaj yeem ua raws li cov hniav thiab txo cov kev ua haujlwm.

4.3 Kev Kho Cov Khoom Siv: Kev Tiv Thaiv Pom Hniav thiab Kev Ua Raws Cai

Kev tu cov cuab yeej siv niaj hnub ua kom pom cov hniav ua tau zoo thiab OSHA ua raws:

• Kev tshuaj ntsuam xyuas: Tshawb xyuas LEV system lub shroud (cov khoom uas nyob ib ncig ntawm cov hniav) rau cov kab nrib pleb los yog misalignment. Lub shroud puas tso cai rau cov plua plav tawm, txawm tias muaj cov saw hlau zoo.
• Hose kev ncaj ncees: Tshawb xyuas LEV system lub hoses rau kinks lossis leaks - txwv airflow txo cov plua plav pov tseg thiab lim cov saw hniav (nce kev sib txhuam los ntawm cov plua plav plua plav).
• Hniav nro: Xyuas kom cov saw hniav yog nruj nruj rau ntawm spindle. Cov hniav xoob vibrates, ua rau chipping thiab hnav ntxov ntxov.

5. Kev Tshawb Fawb Txog Kev Tsim Kho: Tailoring Saw Blades rau Kev Xav Tau Ntau Lawm

Cov xwm txheej tsim khoom - suav nrog ntim, qhov yuav tsum tau ua kom raug, thiab cov qauv kev ua raws - txiav txim siab "tus nqi-kev ua tau zoo" sib npaug ntawm kev xaiv cov hniav.

5.1 Qhuav Volume: Tsawg-Volume vs. High-Volume

• Tsawg ntim ntau lawm (piv txwv li, kev tsim kho ntawm qhov chaw): Prioritize tus nqi-zoo thiab portability. Xaiv HSS los yog TiN-coated carbide hniav (4-6 nti inch) rau qee zaus txiav. Cov hniav no pheej yig thiab yooj yim los hloov, thiab lawv cov kab me me haum rau cov saws tes rau ntawm qhov chaw maneuverability.
• High-ntim ntau lawm (piv txwv li, Hoobkas prefabrication ntawm FCB panels): Prioritize durability thiab efficiency. Xaiv rau DLC-coated carbide hniav (6-8 nti inch) nrog TCG tsim qauv. Cov hniav no tuaj yeem tiv taus kev txiav tsis tu ncua, txo qis qis rau cov hniav hloov. Tsis tas li ntawd, phim lawv rau cov tshuab muaj peev xwm LEV (≥200 CFM rau 8-nti hniav) kom muaj kev ua raws cai thiab kev tsim khoom.

5.2 Txiav Precision Requirements: Structure vs. Decorative

• Cov qauv FCB ​​(piv txwv li, load-bearing panels): Precision yuav tsum yog nruab nrab (± 1mm ​​txiav kam rau ua). Xaiv 24-32 hniav hniav nrog ATB lossis TCG tsim - tsawg dua cov hniav txhim kho kom nrawm, thiab cov hniav zoo txo ​​qis chipping txaus rau kev teeb tsa.
• Kho kom zoo nkauj FCB (xws li, sab hauv phab ntsa panels nrog pom ntug): Precision yuav tsum nruj (± 0.5mm txiav kam rau ua). Xaiv 36-48 hniav hniav nrog ATB tsim thiab DLC txheej. Ntau cov hniav kom cov npoo du, thiab cov txheej tiv thaiv khawb, ua tau raws li cov qauv kev zoo nkauj.

5.3 Kev Ua Raws Cai: OSHA thiab Cov Cai Hauv Zos

OSHA 1926.1153 yog tus qauv tseem ceeb rau FCB txiav, tab sis cov kev cai hauv zos tuaj yeem tsim cov kev cai ntxiv (xws li kev txwv tsis pub muaj plua plav tawm hauv nroog). Thaum xaiv cov saw hniav:

• Plua plav tswj: Xyuas kom cov hniav sib xws nrog LEV systems (piv txwv li, txoj kab uas hla ≤8 ntiv tes, plua plav-funneling matrix) kom tau raws li OSHA qhov kev tiv thaiv silica respirable (50 μg / m³ dhau 8 teev ua haujlwm).
• Kev nyab xeeb daim ntawv lo: Xaiv cov hniav nrog cov ntawv qhia meej meej (piv txwv li, siab tshaj RPM, txoj kab uas hla, cov khoom siv sib xws) kom ua tau raws li OSHA cov khoom siv daim ntawv lo.
• Kev tiv thaiv neeg ua haujlwm: Thaum pom cov hniav tsis ncaj qha muab kev tiv thaiv ua pa, lawv lub peev xwm los txo cov plua plav (los ntawm kev tsim kom zoo) ua tiav OSHA qhov kev xav tau rau APF 10 lub tshuab ua pa hauv cov chaw kaw (txawm tias FCB txiav feem ntau yog sab nraum zoov, raws li kev coj ua zoo tshaj).

6. Daim Ntawv Thov Scenario: Hloov Cov Hniav Hniav rau Ntawm Qhov Chaw

FCB txiav scenarios txawv ntawm ib puag ncig (sab nraum zoov vs. sab hauv tsev), txiav hom (ncaj vs. nkhaus), thiab huab cua tej yam kev mob-tag nrho cov uas cuam tshuam pom hniav xaiv.

6.1 Kev txiav sab nraum zoov (Primary Scenario for FCB)

Raws li OSHA cov kev coj ua zoo tshaj plaws, FCB txiav yognyiam sab nraum zoovtxhawm rau txo cov plua plav kom tsawg (sab hauv tsev txiav yuav tsum tau siv cov pa ntxiv). Sab nraum cov xwm txheej muaj xws li:

• Sab nrauv phab ntsa vaj huam sib luag installation: Yuav tsum tau txiav ntsug thiab precision (kom haum lub qhov rais / qhov rooj qhib). Xaiv 6-nti ATB hniav hniav (36 hniav) nrog TiN txheej - nqa tau siv rau ntawm qhov chaw, thiab cov txheej tiv thaiv sab nraum zoov.
• Ru tsev underlayment txiav: Yuav tsum tau ceev, ncaj txiav ntawm nyias FCB (4-6mm). Xaiv 4-nti TCG hniav hniav (24 hniav) - me me txoj kab uas hla kom yooj yim ru tsev nkag, thiab TCG cov hniav tuav abrasive vov tsev FCB ​​(siab dua silica cov ntsiab lus).
• Huab cua xav txog: Nyob rau hauv cov huab cua ntub lossis los nag, siv cov hniav tiv thaiv corrosion (xws li, stainless hlau matrices). Hauv cov cua kub siab, xaiv cov hniav nrog cov hniav sib npaug kom txo tau kev co (cua tuaj yeem ua kom cov hniav wobble).

6.2 Kev txiav sab hauv tsev (Tshwj xeeb)

Sab hauv FCB ​​txiav (piv txwv li, sab hauv muab faib installation nyob rau hauv lub tsev) tsuas yog tso cai nrogtxhim kho plua plav tswj:

• Pom hniav xaiv: Siv 4-6 nti hniav (txoj kab uas hla me dua = tsawg dua plua plav tiam) nrog DLC ​​txheej (txo cov plua plav adhesion). Zam 8-nti cov hniav nyob hauv tsev - lawv tsim cov plua plav ntau dua, txawm tias muaj cov tshuab LEV.
• Kev pab cuam tso pa tawm: Muab cov saw hniav nrog cov kiv cua nqa tau yooj yim (piv txwv li, axial kiv cua) txhawm rau ntxiv LEV systems, coj cov plua plav mus rau qhov tso pa tawm. Cov hniav lub plua plav-funneling matrix yuav tsum ua raws li tus kiv cua cov kev taw qhia airflow.

6.3 Txiav Hom: Ncaj vs. nkhaus

• Kev txiav ncaj (feem ntau): Siv tag nrho-voj vojvoog hniav (tus qauv ncig pom hniav) nrog ATB lossis TCG cov hniav. Cov hniav no muab kev ruaj khov, ncaj txiav rau panels, studs, los yog trim.
• Curved txiav (piv txwv li, archways): Siv cov hniav nqaim dav (≤0.08 ntiv tes tuab) nrog cov hniav zoo (48 hniav). Cov hniav nyias nyias yog hloov tau yooj yim rau kev txiav nkhaus, thiab cov hniav zoo tiv thaiv chipping ntawm ntug nkhaus. Tsis txhob tuab cov hniav-lawv yog nruj thiab yooj yim tawg thaum txiav nkhaus.

7. Xaus: Lub Cev Txheej Txheem rau Kev Xaiv Cov Hniav

Xaiv txoj cai fiber ntau cement board txiav saw hniav yuav tsum muaj ib tug holistic mus kom ze uas integrates cov yam ntxwv ntawm cov khoom, pom hniav tsis, khoom compatibility, ntau lawm tej yam kev mob, thiab daim ntawv thov scenarios - tag nrho cov thaum ua raws li OSHA cov qauv kev nyab xeeb. Txhawm rau txiav txim siab lub moj khaum xaiv:

1. Pib nrog cov khoom siv: Txheeb xyuas FCB qhov ntom ntom, tuab, thiab cov ntsiab lus silica los txhais cov ntsiab lus ntawm cov saw hniav (xws li, hnav tsis kam rau cov boards siab, kev tswj plua plav rau high-silica boards).
2. Xauv hauv qhov tseem ceeb saw hniav tsis: Ua kom txoj kab uas hla ≤8 ntiv tes (OSHA ua raws), xaiv matrix / hniav / txheej raws li qhov ntim ntau lawm (DLC rau cov ntim siab) thiab qhov tseeb (siab cov hniav suav rau cov hniav txiav).
3. Sib phim rau cov khoom siv: Txheeb xyuas qhov loj me, RPM kev sib raug zoo, thiab LEV system airflow (≥25 CFM / nti) kom ntseeg tau tias kev ua haujlwm zoo thiab kev tswj xyuas plua plav.
4. Ua ke nrog cov xwm txheej tsim khoom: Tus nqi sib npaug thiab kav ntev (tsawg-ntim: HSS; siab-ntim: DLC) thiab ua tau raws li qhov xav tau / ua raws.
5. Hloov mus rau qhov xwm txheej: Ua ntej cov hniav zoo nkauj sab nraum zoov (corrosion-resistant) rau kev ua haujlwm ntawm qhov chaw, thiab siv nqaim, yoog raws cov hniav rau kev txiav nkhaus.

Los ntawm kev ua raws li cov txheej txheem no, cov tuam txhab, cov neeg cog lus, thiab cov neeg tsim khoom tuaj yeem xaiv cov saw hniav uas tsis yog tsuas yog xa cov khoom zoo, zoo FCB txiav tab sis kuj ua kom tau raws li OSHA cov qauv thiab tiv thaiv cov neeg ua haujlwm los ntawm silica plua plav raug-thaum kawg ua tiav qhov sib npaug ntawm kev ua tau zoo, kev nyab xeeb, thiab tus nqi-zoo.