# SPF Ven tila tion Design for In te rior Applic at ion in Exis ting Buildings* Pr esen tat ion by CPI/SPFA Ef fe ctiv e Workplace Pr actices/ HazCom Wo rkgr oup *Including new buildings that cannot be completely vacated – for example commercial construction projects where workers are present in adjacent rooms or floors.

# Objectiv e and Ov er view • Objectiv e: R eview s tat us of e xploration of dual fan vs. single fan v en tilation appr oaches • Pr esen tat ion Ov erview:
– Ve nt ilation
– Syste m Design and Oper ation
– Added Safety Consider ations
– Discussion
– Ne xt St eps

# Ve nt ila tion • Import ance of v en tilation and conta inmen t
– Basis fo r engineering contr ols s tr ate gy fo r safe application of SPF inside e xis ting or occupied buildings
– Helps pr otect occupants and worker s in adjacent ar eas fr om potential chemical e xposur e 

### • Benefits of v en tilation
– In contained workspace, cr ea te s neg ative pr essur e – In non - contained workspace (e.g., high v olume wa re house), dissipates chemicals in air
– Re duce airborne lev els of haz ar dous chemicals during and after application

# Fo cus of Pr esen tat ion • Not all in te rior applications ma y need t andem co nta inmen t/v en tilation; ve ntilation alone ma y be suf

ficien t in some applications • The feasibility of cont ainmen t/v en tilation easibility of cont tilation should be consider ed in in te rior applications, however • This pr esen tat ion focuses on t andem co nta inmen t/v en tilation appr oaches

# Syste m Design Consider at ions • Tw o - Pa rt Design (1) Con ta inmen t
– Wo rk space mus t be nearly airtigh t
– Use plas tic sheeting and tape
– Check with smoke pencil 

### (2) Activ e or F or ced - air Ven tilation

– Single fa n e xhaus te d to ex te rior OR
– Dual fan; e xhaus t + supply

# Syste m Design and Oper at ion • TBL Application is well defined; sizing , location and oper at ion of dual - fa n syste m fans is a ‘stat ic’ pr ocess – Fixed workspace (containment) v olume and geometry
– Kn own application point = limited applicator r ange and mov ement – Fixed fan locations to create fixed cr oss flow v entilation pa th
– Kn own containment leak age r ate
inlet fan ex haust fan Cross - flow ventilation negative pressure if q e > q i leak age, q e - q i q e q i

# Syste m Design and Oper at ion • Interior SPF Application is NOT well defined...and not suited fo r dual - fa n ventilation 1. Variable workspace volume and geometry at each jobsite **lar ge**  **commer cial**  **building Ev** **ery jobsite has a diff**  **erent size and shape small**  **re sidential**  **attic Multiple workspace**  **geometries at each jobsite**

# Syste m Design and Oper at ion • Interior SPF Application is NOT well defined...and not suit ed for dual - fa n ventilation 1. Variable workspace volume and geometry at each jobsite 2. Moving application point - adaptable cross - flow ventilation needed ex haust fan q e 

##  **Ve ry difficult t** **o** inlet fan q i 

##  

#  **Ve ry difficult t** **o control cross**  **** **ventilation without relocating fan(s)** 

# Syste m Design and Oper at ion • Interior SPF Application is NOT well defined...and not suit ed for dual - fa n ventilation 1. Va riable workspace volume and geometry at each jobsite 2. Moving application point - adaptable cross - flow ventilation needed 3. Leakage va ries with each workspace **Leak age Rates...**  • **not always proportional to volume**  **Low leakage** in **lar ge**  **containment** volume **to volume** • **change as SPF is applied Proper**  **fan sizing and**  **balancing is a challenge to maintain fix** 

**ed ventilation rate**  **High leakage** in **small containment**  volumeex haust fan q e 

# Syste m Design and Oper at ion • Interior SPF Application is NOT well defined...and not suit ed for dual - fa n ventilation 1. Va riable workspace volume and geometry at each jobsite 2. Moving application point - adaptable cross - flow ventilation needed 3. Leakage va ries with each workspace 4. Fa ns can be improperly set up **Dual fan systems can**  positive pressure if q e < q i inlet fan q i **Dual fan systems can**  **pressurize workspaces and force contaminated**  **air OUTSIDE the containment**  **workzone -**  **creating hazards for occupants and other**  **workers if not balanced properly**  

## 

# Added Sa fe ty Haz ar ds • Tr ip Haz ar d Cr ea te d
– Low ligh t levels in man y w ork spaces – Limit ed visibility thr ough supplied air respir ato rs – Limit ed body movement/co ntro l wearing PPE
– Cor ds and ducts fr om e xhaust fans ar e trip haz ar d
– Tr ipping is especially dang er ous in attics ipping is especially dang ous in at

# Added Sa fe ty Haz ar ds • Emergency Egr ess Blocked
– Exhaus t fa n ducts thr ough attic hatches, windows and doorw ay s limit or pr event emerge ncy egr ess 

### • Contamination Risk
– Fo am and chemical dr oplets that accumulate on ve nt ilation ductwork could be deposited in occupied spaces during tr ans fe r and r elocation

# EWP /HC Wo rkgr oup Appr oach

– Additional guidance can be pr ovided to educate about workspace containment and neg ative pr essur e
– Dual - fa n v en tilation syste m **will not be eff ective**  • Will not pr ovide sufficient or consistent cr oss ve nt ilation in workspace to eliminate use of SAR • To o difficult to design, set up and oper ate in the field • Cr ea te s additional worker safety issues that offset an y re duction in air concentr ations Approach: develop and provide guidance on work space co nta inment plus single -

fa n ventilation strategy

# EWP /HC Wo rkgr oup Appr oach • Wo rkspace Con ta inmen t
– 4 - 6 mil PE (Visqueen) sheeting
– Overlap seams and seal with tape
– Pr oper haz ar d warning signs
– Te stwith smoke pencil or differ en tial manomet er

# EWP /HC Wo rkgr oup Appr oach • Single Fa n Ven tila tion
– Use as e xhaust fa n ONL Y
– Gr eatly r educes risk of fan imbalance or impr oper setup – Neg at iv e pr essur e in workspace • Va lidate with manometer or inward billowing of sheeting 

### – Siz e to deliver ~0.3 - 1.0 ACH minimum • Neg ative workplace pressure generation only • Not for c on ta minan t level reduction 

### – Minimiz es ducts and cor ds on floor of w ork ar ea – Minimiz es block ag e of emerge ncy egr ess

# EWP Wo rkgr oup Appr oach **Single -**  **Fa n**  **Ve ntilation Concept**  (negative pressure only)

# EWP

/HC Ne xt St ep s • Get Agency fe edback on single - fa n v entilation concept • Dev elop four - page guidance document for SPF applicators
– Wo rkspace containment
– Single fan v entilation appr oach
– Consult ‘Br eathe E asy’ document for formatting and presentation Consult ‘Br eathe E document f ormatting and presentation • Seek EP

A/NIOSH/OSHA input in February • Disseminate guidance; integr ate guidance into e xisting materials (upda te to reflect ventilation guidance)